Found 44 papers in cond-mat The highly tunable nature of synthetic quantum materials -- both in the
solid-state and cold atom contexts -- invites examining which microscopic
ingredients aid in the realization of correlated phases of matter such as
superconductors. Recent experimental advances in moir\'e materials suggest that
unifying the features of the Fermi-Hubbard model and quantum Hall systems
creates a fertile ground for the emergence of such phases. Here, we introduce a
minimal 2D lattice model that incorporates exactly these features:
time-reversal symmetry, band topology, and strong repulsive interactions. By
using infinite cylinder density matrix renormalization group methods (cylinder
iDMRG), we investigate the ground state phase diagram of this model. We find
that it hosts an interaction-induced quantum spin Hall (QSH) insulator and
demonstrate that weakly hole-doping this state gives rise to a superconductor
at a finite circumference, with indications that this behavior persists on
larger cylinders. At the aforementioned circumference, the superconducting
phase is surprisingly robust to perturbations including additional repulsive
interactions in the pairing channel. By developing a technique to probe the
superconducting gap function in iDMRG, we phenomenologically characterize the
superconductor. Namely, we demonstrate that it is formed from the weak pairing
of holes atop the QSH insulator. Furthermore, we determine the pairing symmetry
of the superconductor, finding it to be $p$-wave -- reminiscent of the
unconventional superconductivity reported in experiments on twisted bilayer
graphene (TBG). Motivated by this, we elucidate structural similarities and
differences between our model and those of TBG in its chiral limit. Finally, to
provide a more direct experimental realization, we detail an implementation of
our Hamiltonian in a system of cold fermionic alkaline-earth atoms in an
optical lattice.
It is a matter of current debate whether the gate-tunable superconductivity
in twisted bilayer graphene is phonon-mediated or arises from electron-electron
interactions. The recent observation of the strong coupling of electrons to
so-called $K$-phonon modes in angle-resolved photoemission spectroscopy
experiments has resuscitated early proposals that $K$-phonons drive
superconductivity. We show that the bandwidth-enhancing effect of interactions
drastically weakens both the intrinsic susceptibility towards pairing as well
as the screening of Coulomb repulsion that is essential for the phonon
attraction to dominate at low temperature. This rules out purely
$K$-phonon-mediated superconductivity with the observed transition temperature
of $\sim 1$ K. We conclude that the unflattening of bands by Coulomb
interactions challenges any purely phonon-driven pairing mechanism, and must be
addressed by a successful theory of superconductivity in moir\'e graphene.
Probabilistic computing is a novel computing scheme that offers a more
efficient approach than conventional CMOS-based logic in a variety of
applications ranging from optimization to Bayesian inference, and invertible
Boolean logic. The probabilistic-bit (or p-bit, the base unit of probabilistic
computing) is a naturally fluctuating entity that requires tunable
stochasticity; by coupling low-barrier stochastic Magnetic Tunnel Junctions
(MTJs) with a transistor circuit, a compact implementation is achieved. In this
work, through integrating stochastic MTJs with 2D-MoS$_{2}$ FETs, the first
on-chip realization of a key p-bit building block displaying
voltage-controllable stochasticity is demonstrated. In addition, supported by
circuit simulations, this work provides a careful analysis of the three
transistor-one magnetic tunnel junction (3T-1MTJ) p-bit design, evaluating how
the characteristics of each component influence the overall p-bit output. This
understanding of the interplay between the characteristics of the transistors
and the MTJ is vital for the construction of a fully functioning p-bit, making
the design rules presented in this article key for future experimental
implementations of scaled on-chip p-bit networks.
Magnetic skyrmions are vortex-like quasiparticles characterized by long
lifetime and remarkable topological properties. That makes them a promising
candidate for the role of information carriers in magnetic information storage
and processing devices. Although considerable progress has been made in
studying skyrmions in classical systems, little is known about the quantum
case: quantum skyrmions cannot be directly observed by probing the local
magnetization of the system, and the notion of topological protection is
elusive in the quantum realm. Here, we explore the potential robustness of
quantum skyrmions in comparison to their classical counterparts. We
theoretically analyze the dynamics of a quantum skyrmion subject to local
projective measurements and demonstrate that the properties of the skyrmionic
quantum state change very little upon external perturbations. We further show
that by performing repetitive measurements on a quantum skyrmion, it can be
completely stabilized through an analog of the quantum Zeno effect.
Despite fascinating experimental results, the influence of defects and
elastic strains on the physical state of nanosized ferroelectrics is still
poorly explored theoretically. One of unresolved theoretical problems is the
analytical description of the strongly enhanced spontaneous polarization,
piezoelectric response, and dielectric properties of ferroelectric oxide thin
films and core-shell nanoparticles induced by elastic strains and stresses. In
particular, the 10-nm quasi-spherical BaTiO$_3$ core-shell nanoparticles reveal
a giant spontaneous polarization up to 130 mu_C/cm2, where the physical origin
is a large Ti off-centering. The available theoretical description cannot
explain the giant spontaneous polarization observed in these spherical
nanoparticles. This work analyzes polar properties of BaTiO$_3$ core-shell
spherical nanoparticles using the Landau-Ginzburg-Devonshire approach, which
considers the nonlinear electrostriction coupling and large Vegard strains in
the shell. We reveal that a spontaneous polarization greater than 50 mu_C/cm2
can be stable in a (10-100) nm BaTiO$_3$ core at room temperature, where a 5 nm
paraelectric shell is stretched by (3-6)% due to Vegard strains, which
contribute to the elastic mismatch at the core-shell interface. The large
polarization corresponds to very high tetragonality ratios (1.02-1.04), which
is further increased by higher Vegard strains and/or intrinsic surface stresses
leading to unphysically high tetragonality ratios. The nonlinear
electrostriction coupling and the elastic mismatch at the core-shell interface
are key physical factors of the spontaneous polarization enhancement in the
core. Doping with the highly-polarized core-shell nanoparticles can be useful
in optoelectronics and nonlinear optics to increase beam coupling efficiency,
electric field enhancement, reduced switching voltages, ionic contamination
elimination, and catalysis.
Moir\'e superlattices of semiconducting transition metal dichalcogenides
(TMDCs) enable unprecedented spatial control of electron wavefunctions in an
artificial lattice with periodicities more than ten times larger than that of
atomic crystals, leading to emerging quantum states with fascinating electronic
and optical properties. The breaking of translational symmetry further
introduces a new degree of freedom inside each moir\'e unit cell: high symmetry
points of energy minima called moir\'e sites, behaving as spatially separated
quantum dots. The superposition of a quasiparticle wavefunction between
different moir\'e sites will enable a new platform for quantum information
processing but is hindered by the suppressed electron tunneling between moir\'e
sites. Here we demonstrate the superposition between two moir\'e sites by
constructing an angle-aligned trilayer WSe2/monolayer WS2 moir\'e
heterojunction. The two moir\'e sites with energy minimum allow the formation
of two different interlayer excitons, with the hole residing in either moir\'e
site of the first WSe2 layer interfacing the WS2 layer and the electron in the
third WSe2 layer. An external electric field can drive the hybridization of
either of the interlayer excitons with the intralayer excitons in the third
WSe2 layer, realizing the continuous tuning of interlayer exciton hopping
between two moir\'e sites. Therefore, a superposition of the two interlayer
excitons localized at different moir\'e sites can be realized, which can be
resolved in the electric-field-dependent optical reflectance spectra,
distinctly different from that of the natural trilayer WSe2 in which the
moir\'e modulation is absent. Our study illustrates a strategy of harnessing
the new moir\'e site degree of freedom for quantum information science, a new
direction of twistronics.
We analyze potential non-analytic terms in the Landau diamagnetic
susceptibility, $\chi_{dia}$, at a finite temperature $T$ and/or finite
magnetic field $H$. To do this, we express the diamagnetic susceptibility as
$\chi_{dia} = (e/c)^2 \lim_{Q\rightarrow0} \Pi^{JJ}_\perp (Q)/Q^2$, where
$\Pi^{JJ}_\perp$ is the transverse component of the static current-current
correlator, and evaluate $\Pi^{JJ}_\perp (Q)$ for a system of fermions with
Hubbard interaction to second order in Hubbard $U$ by combining self energy,
Maki-Thompson, and Aslamazov-Larkin diagrams. We find that at $T=H=0$, the
expansion of $\Pi^{JJ}_\perp (Q)/Q^2$ in $U$ is regular, but at a finite $T$
and/or $H$, it contains $U^2 T$ and/or $U^2 |H|$ terms. Similar terms have been
previously found for the paramagnetic Pauli susceptibility. We obtain the full
expression for the non-analytic $\delta \chi_{dia} (H,T)$ when both $T$ and $H$
are finite, and show that the $H/T$ dependence is similar to that for the Pauli
susceptibility.
We theoretically study topological properties of Floquet magnon in a
laser-irradiated Kitaev-Heisenberg honeycomb ferromagnet with the
Dzyaloshinskii-Moriya interaction by means of the Floquet-Bloch theory. It is
found that the Kitaev-Heisenberg ferromagnet can reveal two topological phases
with different Chern numbers when it is irradiated by a circular-polarized
light laser. Our results show that the topological phase of the system can be
switched from one topological phase to another one via varying the light
intensity. The intrinsic DMI plays a crucial role in the occurrence of
photoinduced topological phase transition. It is shown that the sign reversal
of the thermal hall conductivity is an important indicator on photoinduced
topological phase transitions in the Kitaev-Heisenberg honeycomb ferromagnet.
In magnetic memories, the state of a ferromagnet is encoded in the
orientation of its magnetization. The energy of the system is minimized when
the magnetization is parallel or antiparallel to a preferred (easy) axis. These
two stable directions define the logical bit. Under an external perturbation,
the direction of magnetization can be controllably reversed and thus the bit
flipped. Here, we theoretically design a topological analogue of the magnetic
bit in the Su-Schrieffer-Heeger (SSH)-Holstein model, where we show that a
transient external perturbation can lead to a permanent change in the
electronic band topology.
Electronic liquid-crystal phases are observed in numerous strongly-correlated
systems including high-temperature superconductors. However, identifying these
exotic phases and understanding their interplay with superconductivity in
topological materials remain challenging. Here we employ a cryogenic scanning
tunneling microscopy to discover a smectic (stripe) charge order (CO) and a
primary pair-density-wave (PDW) in topological monolayer 1T$^\prime$-MoTe$_2$.
The two orders are spatially modulated unidirectionally at the same wavevector,
but have a marked spatial phase difference of about 2$\pi$/5. Importantly, the
primary PDW state features a two-gap superconductivity below the transition
temperature of 6.0 K and induces another unique particle-hole-symmetric CO at
twice the PDW wavevector. Combining these results and our density functional
calculations, we reveal that the two smectic orders are primarily driven by
nesting behaviors between electron and hole pockets. Our findings establish
monolayer 1T$^\prime$-MoTe$_2$ as a topological paradigm for exploring
electronic smecticity, which intertwines with multiple preexisting
symmetry-breaking states.
Hybridization of excitons with photons to form hybrid quasiparticles,
exciton-polaritons (EPs), has been widely investigated in a range of
semiconductor material systems coupled to photonic cavities. Self-hybridization
occurs when the semiconductor itself can serve as the photonic cavity medium
resulting in strongly-coupled EPs with Rabi splitting energies > 200 meV at
room temperatures which recently were observed in layered two-dimensional (2D)
excitonic materials. Here, we report an extreme version of this phenomenon, an
ultrastrong EP coupling, in a nascent, 2D excitonic system, the metal organic
chalcogenate (MOCHA) compound named mithrene. The resulting self-hybridized EPs
in mithrene crystals placed on Au substrates show Rabi Splitting in the
ultrastrong coupling range (> 600 meV) due to the strong oscillator strength of
the excitons concurrent with the large refractive indices of mithrene. We
further show bright EP emission at room temperature as well as EP dispersions
at low-temperatures. Importantly, we find lower EP emission linewidth narrowing
to ~1 nm when mithrene crystals are placed in closed Fabry-Perot cavities. Our
results suggest that MOCHA materials are ideal for polaritonics in the deep
green-blue part of the spectrum where strong excitonic materials with large
optical constants are notably scarce.
We present the successful realization of four-dimensional (4D) semimetal
bands featuring tensor monopoles, achieved using superconducting quantum
circuits. Our experiment involves the creation of a highly tunable diamond
energy diagram with four coupled transmons, and the parametric modulation of
their tunable couplers, effectively mapping momentum space to parameter space.
This approach enables us to establish a 4D Dirac-like Hamiltonian with fourfold
degenerate points. Moreover, we manipulate the energy of tensor monopoles by
introducing an additional pump microwave field, generating effective magnetic
and pseudo-electric fields and simulating topological parity magnetic effects
emerging from the parity anomaly. Utilizing non-adiabatic response methods, we
measure the fractional second Chern number for a Dirac valley with a varying
mass term, signifying a nontrivial topological phase transition connected to a
5D Yang monopole. Our work lays the foundation for further investigations into
higher-dimensional topological states of matter and enriches our comprehension
of topological phenomena.
Iron manganese trioxide (FexMn1-x)2O3 nanocrystals were synthesized by the
sol-gel method. The 80 K Mossbauer spectrum was well-fitted using two doublets
representing the 8b and 24d crystallographic sites of the (FexMn1-x)2O3 phase
and two weak extra sextets which were attributed to crystalline and amorphous
hematite. Our findings showed formation of a bixbyite primary phase. The Raman
spectrum exhibits six Raman active modes, typical of (Fe,Mn)2O3, and two extra
Raman modes associated with the secondary hematite phase. X-ray photoelectron
spectroscopy analysis confirmed the presence of oxygen vacancy onto the
(FexMn1-x)2O3 particle surface, with varying oxidation states. X-band magnetic
resonance data revealed a single broad resonance line in the whole temperature
range (3.8 K - 300 K). The temperature dependence of both resonance field and
resonance linewidth shows a remarkable change in the range of 40 - 50 K, herein
credited to surface spin glass behavior. The model picture used assumes
(FexMn1-x)2O3 nanoparticles with a core-shell structure. Results indicate that
below about 50 K the spin system of shell reveals a paramagnetic to spin
glass-like transition upon cooling, with a critical temperature estimated at 43
K. In the higher temperature range, the superparamagnetic hematite (secondary)
phase contributes remarkably to the temperature dependence of the resonance
linewidth. Zero-field-cooled (ZFC) and fieldcooled (FC) data show strong
irreversibility and a peak in the ZFC curve at 33 K, attributed to a
paramagnetic-ferrimagnetic transition of the main phase. Hysteresis curve at 5
K shows a low coercive field of 4 kOe, with the magnetization not reaching
saturation at 70 kOe, suggesting the occurrence of a ferrimagnetic core with a
magnetic disorder at surface, characteristic of core-shell spin-glass-like
behavior.
We investigate symmetry breaking in the Dirac fermion phase of the organic
compound $\alpha$-(BEDT-TTF)$_2$I$_3$ under pressure, where BEDT-TTF denotes
bis(ethylenedithio)tetrathiafulvalene. The exchange interaction resulting from
inter-molecule Coulomb repulsion leads to broken time-reversal symmetry and
particle-hole symmetry while preserving translational symmetry. The system
breaks time-reversal symmetry by creating fluxes in the unit cell. This
symmetry-broken state exhibits a large Nernst signal as well as thermopower. We
compute the Nernst signal and thermopower, demonstrating their consistency with
experimental results.
We report on the tuning of electrical, magnetic, and topological properties
of the magnetic Weyl semimetal (Mn$_{3+x}$Ge) by Fe doping at the Mn site,
Mn$_{(3+x)-\delta}$Fe$_{\delta}$Ge ($\delta$=0, 0.30, and 0.62). Fe doping
significantly changes the electrical and magnetic properties of Mn$_{3+x}$Ge.
The resistivity of the parent compound displays metallic behavior, the system
with $\delta$=0.30 of Fe doping exhibits semiconducting or bad-metallic
behavior, and the system with $\delta$=0.62 of Fe doping demonstrates a
metal-insulator transition at around 100 K. Further, we observe that the Fe
doping increases in-plane ferromagnetism, magnetocrystalline anisotropy, and
induces a spin-glass state at low temperatures. Surprisingly, topological Hall
state has been noticed at a Fe doping of $\delta$=0.30 that is not found in the
parent compound or with $\delta$=0.62 of Fe doping. In addition, spontaneous
anomalous Hall effect observed in the parent system is significantly reduced
with increasing Fe doping concentration.
Branched flow governs the transition from ballistic to diffusive motion of
waves and conservative particle flows in spatially correlated random or complex
environments. It occurs in many physical systems from micrometer to
interstellar scales. In living matter systems, however, this transport regime
is usually suppressed by dissipation and noise. In this article we demonstrate
that, nonetheless, noisy active random walks, characterizing many living
systems like foraging animals, and chemotactic bacteria, can show a regime of
branched flow. To this aim we model the dynamics of trail forming ants and use
it to derive a scaling theory of branched flows in active random walks in
random bias fields in the presence of noise. We also show how trail patterns,
formed by the interaction of ants by depositing pheromones along their
trajectories, can be understood as a consequence of branched flow.
Hydrodynamic interactions can give rise to a collective motion of rotating
particles. This, in turn, can lead to coherent fluid flows. Using large scale
hydrodynamic simulations, we study the coupling between these two in spinner
monolayers at weakly inertial regime. We observe an instability, where the
initially uniform particle layer separates into particle void and particle rich
areas. The particle void region corresponds to a fluid vortex, and it is driven
by a surrounding spinner edge current. We show that the instability originates
from a hydrodynamic lift force between the particle and fluid flows. The
cavitation can be tuned by the strength of the collective flows. It is
suppressed when the spinners are confined by a no-slip surface, and multiple
cavity and oscillating cavity states are observed when the particle
concentration is reduced.
The out-of-thermal-equilibrium Casimir-Polder force between nanoparticles and
dielectric substrates coated with gapped graphene is considered in the
framework of the Dirac model using the formalism of the polarization tensor.
This is an example of physical phenomena violating the time-reversal symmetry.
After presenting the main points of the used formalism, we calculate two
contributions to the Casimir-Polder force acting on a nanoparticle on the
source side of a fused silica glass substrate coated with gapped graphene,
which is either cooler or hotter than the environment. The total nonequilibrium
force magnitudes are computed as a function of separation for different values
of the energy gap and compared with those from an uncoated plate and with the
equilibrium force in the presence of graphene coating. According to our
results, the presence of a substrate increases the magnitude of the
nonequlibrium force. The force magnitude becomes larger with higher and smaller
with lower temperature of the graphene-coated substrate as compared to the
equilibrium force at the environmental temperature. It is shown that with
increasing energy gap the magnitude of the nonequilibrium force becomes
smaller, and the graphene coating makes a lesser impact on the force acting on
a nanoparticle from the uncoated substrate. Possible applications of the
obtained results are discussed.
How strong correlations and topology interplay is a topic of great current
interest. In this perspective paper, we focus on correlation-driven gapless
phases. We take the time-reversal symmetric Weyl semimetal as an example
because it is expected to have clear (albeit nonquantized) topological
signatures in the Hall response and because the first strongly correlated
representative, the noncentrosymmetric Weyl-Kondo semimetal Ce$_3$Bi$_4$Pd$_3$,
has recently been discovered. We summarize its key characteristics and use them
to construct a prototype Weyl-Kondo semimetal temperature-magnetic field phase
diagram. This allows for a substantiated assessment of other Weyl-Kondo
semimetal candidate materials. We also put forward scaling plots of the
intrinsic Berry-curvature-induced Hall response vs the inverse Weyl velocity --
a measure of correlation strength, and vs the inverse charge carrier
concentration -- a measure of the proximity of Weyl nodes to the Fermi level.
They suggest that the topological Hall response is maximized by strong
correlations and small carrier concentrations. We hope that our work will guide
the search for new Weyl-Kondo semimetals and correlated topological semimetals
in general, and also trigger new theoretical work.
The adsorption/desorption of ethene (C2H4), also commonly known as ethylene,
on Fe3O4(001) was studied under ultrahigh vacuum conditions using temperature
programmed desorption (TPD), scanning tunneling microscopy, x-ray photoelectron
spectroscopy, and density functional theory (DFT) based computations. To
interpret the TPD data, we have employed a new analysis method based on
equilibrium thermodynamics. C2H4 adsorbs intact at all coverages and interacts
most strongly with surface defects such as antiphase domain boundaries and Fe
adatoms. On the regular surface, C2H4 binds atop surface Fe sites up to a
coverage of 2 molecules per (rt2xrt2)R45{\deg} unit cell, with every second Fe
occupied. A desorption energy of 0.36 eV is determined by analysis of the TPD
spectra at this coverage, which is approximately 0.1-0.2 eV lower than the
value calculated by DFT + U with van der Waals corrections. Additional
molecules are accommodated in between the Fe rows. These are stabilized by
attractive interactions with the molecules adsorbed at Fe sites. The total
capacity of the surface for C2H4 adsorption is found to be close to 4 molecules
per (rt2xrt2)R45{\deg} unit cell.
Magnetic skyrmions are nano-sized topologically non-trivial spin textures
that can be moved by external stimuli such as spin currents and internal
stimuli such as spatial gradients of a material parameter. Since the total
energy of a skyrmion depends linearly on most of these parameters, like the
perpendicular magnetic anisotropy, the exchange constant, or the
Dzyaloshinskii-Moriya interaction strength, a skyrmion will move uniformly in a
weak parameter gradient. In this paper, we show that the linear behavior
changes once the gradients are strong enough so that the magnetic profile of a
skyrmion is significantly altered throughout the propagation. In that case, the
skyrmion experiences acceleration and moves along a curved trajectory.
Furthermore, we show that when spin-orbit torques and material parameter
gradients trigger a skyrmion motion, it can move on a straight path along the
current or gradient direction. We discuss the significance of suppressing the
skyrmion Hall effect for spintronic and neuromorphic applications of skyrmions.
Lastly, we extend our discussion and compare it to a gradient generated by the
Dzyaloshinskii-Moriya interaction.
Measuring large electrical resistances forms an essential part of common
applications such as insulation testing, but suffers from a fundamental
problem: the larger the resistance, the less sensitive a canonical ohmmeter is.
Here we develop a conceptually different electronic sensor by exploiting the
topological properties of non-Hermitian matrices, whose eigenvalues can show an
exponential sensitivity to perturbations. The ohmmeter is realized in an
multi-terminal, linear electric circuit with a non-Hermitian conductance
matrix, where the target resistance plays the role of the perturbation. We
inject multiple currents and measure a single voltage in order to directly
obtain the value of the resistance. The relative accuracy of the device
increases exponentially with the number of terminals, and for large resistances
outperforms a standard measurement by over an order of magnitude. Our work
paves the way towards leveraging non-Hermitian conductance matrices in
high-precision sensing.
Extracting Hamiltonian parameters from available experimental data is a
challenge in quantum materials. In particular, real-space spectroscopy methods
such as scanning tunneling spectroscopy allow probing electronic states with
atomic resolution, yet even in those instances extracting effective Hamiltonian
is an open challenge. Here we show that impurity states in modulated systems
provide a promising approach to extracting non-trivial Hamiltonian parameters
of a quantum material. We show that by combining the real-space spectroscopy of
different impurity locations in a moire topological superconductor, modulations
of exchange and superconducting parameters can be inferred via machine
learning. We demonstrate our strategy with a physically-inspired harmonic
expansion combined with a fully-connected neural network that we benchmark
against a conventional convolutional architecture. We show that while both
approaches allow extracting exchange modulations, only the former approach
allows inferring the features of the superconducting order. Our results
demonstrate the potential of machine learning methods to extract Hamiltonian
parameters by real-space impurity spectroscopy as local probes of a topological
state.
Clean oxide surfaces are generally hydrophilic. Water molecules anchor at
undercoordinated surface metal atoms that act as Lewis-acid sites, and they are
stabilized by H bonds to undercoordinated surface oxygens. The large unit cell
of In2O3(111) provides surface atoms in various configurations, which leads to
chemical heterogeneity and a local deviation from this general rule.
Experiments (TPD, XPS, ncAFM) agree quantitatively with DFT calculations and
show a series of distinct phases. The first three water molecules dissociate at
one specific area of the unit cell and desorb above room temperature. The next
three adsorb as molecules in the adjacent region. Three more water molecules
rearrange this structure and an additional nine pile up above the OH groups.
Despite offering undercoordinated In and O sites, the rest of the unit cell is
unfavorable for adsorption and remains water-free. The first water layer thus
shows ordering into nanoscopic 3D water clusters separated by hydrophobic
pockets.
Indium oxide offers optical transparency paired with electric conductivity, a
combination required in many optoelectronic applications. The most-stable
In2O3(111) surface has a large unit cell (1.43 nm lattice constant). It
contains a mixture of both bulk-like and undercoordinated O and In atoms and
provides an ideal playground to explore the interaction of surfaces with
organic molecules of similar size as the unit cell. Non-contact atomic force
microscopy (nc-AFM), scanning tunneling microscopy (STM), and density
functional theory (DFT) were used to study the adsorption of Co-phthalocyanine
(CoPc) on In2O3(111). Isolated CoPc molecules adsorb at two adsorption sites in
a 7:3 ratio. The Co atom sits either on top of a surface oxygen ('F
configuration') or indium atom ('S configuration'). This subtle change in
adsorption site induces bending of the molecules, which is reflected in their
electronic structure. According to DFT the lowest unoccupied molecular orbital
of the undistorted gas-phase CoPc remains mostly unaffected in the F
configuration but is filled by one electron in S configuration. At coverages up
to one CoPc molecule per substrate unit cell, a mixture of domains with
molecules in F and S configuration are found. Molecules at F sites first
condense into a F-(2x2) structure and finally rearrange into a F-(1x1) symmetry
with partially overlapping molecules, while S-sited molecules only assume a
S-(1x1) superstructure.
In twisted MoTe$_{2}$, latest transport measurement has reported observation
of quantum anomalous Hall effect at hole filling $\nu=-1$, which undergoes a
topological phase transition to a trivial ferromagnet as layer hybridization
gets suppressed by interlayer bias $D$. Here we show that this underlies the
existence of an orbital Chern insulating state with gate ($D$) switchable sign
in an altermagnetic spin background at hole filling $\nu=-2$. From
momentum-space Hartree Fock calculations, we find this state has a topological
phase diagram complementary to that of the $\nu=-1$ one: by sweeping $D$ from
positive to negative, the Chern number of this $\nu=-2$ state can be switched
between $+1$, $0$, and $-1$, accompanied by a sign change of a sizable orbital
magnetization. In range of $D$ where this altermagnet is the ground state, the
orbital magnetization allows magnetic field initialization of the spin
altermagnetic order and the Chern number.
Macroscopic mechanical properties of polymers are determined by their
microscopic molecular chain distribution. Due to randomness of these molecular
chains, probability theory has been used to find their micro-states and energy
distribution. In this paper, aided by central limit theorem and mixed Bayes
rule, we showed that entropy elasticity based on Gaussian distribution is
questionable. By releasing freely jointed chain assumption, we found that there
is energy redistribution when each bond of a molecular chain changes its
length. Therefore, we have to change Gaussian distribution used in polymer
elasticity to Maxwell-Boltzmann distribution. Since Maxwell-Boltzmann
distribution is only a good energy description for gas molecules, we found a
mathematical path to change Maxwell-Boltzmann distribution to Fermi-Dirac
distribution based on molecular chain structures. Because a molecular chain can
be viewed as many monomers glued by covalent electrons, Fermi-Dirac
distribution describes the probability of covalent electron occupancy in
micro-states for solids such as polymers. Mathematical form of Fermi-Dirac
distribution is logistic function. Mathematical simplicity and beauty of
Fermi-Dirac distribution make many hard mechanics problems easy to understand.
Generalized logistic function or Fermi-Dirac distribution function was able to
understand many polymer mechanics problems such as viscoelasticity [1],
viscoplasticity [2], shear band and necking [3], and ultrasonic bonding [4].
Second-order nonlinearity in solids gives rise to a plethora of unique
physical phenomena ranging from piezoelectricity and optical rectification to
optical parametric amplification, spontaneous parametric down-conversion, and
the generation of entangled photon pairs. Monolayer transition metal
dichalcogenides (TMDs), such as MoS$_2$, exhibit one of the highest known
second-order nonlinear coefficients. However, the monolayer nature of these
materials prevents the fabrication of resonant objects exclusively from the
material itself, necessitating the use of external structures to achieve
optical enhancement of nonlinear processes. Here, we exploit the 3R phase of a
molybdenum disulfide multilayer for resonant nonlinear nanophotonics. The lack
of inversion symmetry, even in the bulk of the material, provides a combination
of a massive second-order susceptibility, an extremely high and anisotropic
refractive index in the near-infrared region ($n>$~4.5), and low absorption
losses, making 3R-MoS$_2$ highly attractive for nonlinear nanophotonics. We
demonstrate this by fabricating 3R-MoS$_2$ nanodisks of various radii, which
support resonant anapole states, and observing substantial ($>$ 100-fold)
enhancement of second-harmonic generation in a single resonant nanodisk
compared to an unpatterned flake of the same thickness. The enhancement is
maximized at the spectral overlap between the anapole state of the disk and the
material resonance of the second-order susceptibility. Our approach unveils a
powerful tool for enhancing the entire spectrum of optical second-order
nonlinear processes in nanostructured van der Waals materials, thereby paving
the way for nonlinear and quantum high-index TMD-nanophotonics.
We have combined the benefits of two catalytic growth phenomena to form
nanostructures of transition metal trichalcogenides (TMTs), materials that are
challenging to grow in a nanostructured form by conventional techniques, as
required to exploit their exotic physics. Our growth strategy combines the
benefits of vapor-liquid-solid (VLS) growth in controlling dimension and growth
location, and salt-assisted growth for fast growth at moderate temperatures.
This salt-assisted VLS growth is enabled through use of a catalyst that
includes Au and an alkali metal halide. We demonstrate high yields of NbS3 1D
nanostructures with sub-ten nanometer diameter, tens of micrometers length, and
distinct 1D morphologies consisting of nanowires and nanoribbons with [010] and
[100] growth orientations, respectively. We present strategies to control the
growth location, size, and morphology. We extend the growth method to
synthesize other TMTs, NbSe3 and TiS3, as nanowires. Finally, we discuss the
growth mechanism based on the relationships we measure between the materials
characteristics (growth orientation, morphology and dimensions) and the growth
conditions (catalyst volume and growth time). Our study introduces
opportunities to expand the library of emerging 1D vdW materials and their
heterostructures with controllable nanoscale dimensions.
Surface-enhanced Raman spectroscopy (SERS) is enabled by local surface
plasmon resonances (LSPRs) in metallic nanogaps. When SERS is excited by direct
illumination of the nanogap, the background heating of lattice and electrons
can prevent further manipulation of the molecules. To overcome this issue, we
report SERS in electromigrated gold molecular junctions excited remotely:
surface plasmon polaritons (SPPs) are excited at nearby gratings, propagate to
the junction, and couple to the local nanogap plasmon modes. Like direct
excitation, remote excitation of the nanogap can generate both SERS emission
and an open-circuit photovoltage (OCPV). We compare SERS intensity and OCPV in
both direct and remote illumination configurations. SERS spectra obtained by
remote excitation are much more stable than those obtained through direct
excitation when photon count rates are comparable. By statistical analysis of
33 devices, coupling efficiency of remote excitation is calculated to be around
10%, consistent with the simulated energy flow.
The performance of an organic-semiconductor device is critically determined
by the geometric alignment, orientation, and ordering of the organic molecules.
While an organic multilayer eventually adopts the crystal structure of the
organic material, the alignment and configuration at the interface with the
substrate/electrode material is essential for charge injection into the organic
layer. This work focuses on the prototypical organic semiconductor
para-sexiphenyl (6P) adsorbed on In$_2$O$_3$(111), the thermodynamically most
stable surface of the material that the most common transparent conducting
oxide, indium tin oxide (ITO) is based on. The onset of nucleation and
formation of the first monolayer are followed with atomically-resolved scanning
tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM).
Annealing to 200$^\circ$C provides sufficient thermal energy for the molecules
to orient themselves along the high-symmetry directions of the surface, leading
to a single adsorption site. The AFM data suggests a twisted adsorption
geometry. With increasing coverage, the 6P molecules first form a loose network
with poor long-range order. Eventually the molecules re-orient and form an
ordered monolayer. This first monolayer has a densely packed, well-ordered
(2$\times$1) structure with one 6P per In$_2$O$_3$(111) substrate unit cell,
i.e., a molecular density of 5.64$\times$10$^{13}$ cm$^{-2}$.
We analyse the splitting of exact flat bands in the chiral model of the
twisted bilayer graphene (TBG) when the $AA'/BB'$ coupling of the full
Bistritzer--MacDonald model is taken into account. The first-order perturbation
caused by the $AA'/BB'$ potential the same for both bands and satisfies
interesting symmetries, in particular it vanishes on the line defined by the
$K$ points. The splitting of the flat bands is governed by the quadratic term
which vanishes at the $K$ points.
Using one-dimensional tight-binding lattices and an analytical expression
based on the Green's matrix, we show that anomalous minimum of the localization
length near an isolated flat band, previously found for evanescent waves in a
defect-free photonic crystal waveguide, is a generic feature and exists in the
Anderson regime as well, i.e., in the presence of disorder. Our finding reveals
a scaling behavior of the localization length in terms of the disorder
strength, as well as a summation rule of the inverse localization length in
terms of the density of states in different bands. Most interesting, the latter
indicates the possibility of having two localization minima inside a band gap,
if this band gap is formed by two flat bands such as in a double-sided Lieb
lattice.
Unconventional superconductors represent one of the fundamental directions in
modern quantum materials research. In particular, nodal superconductors are
known to appear naturally in strongly correlated systems, including cuprate
superconductors and heavy-fermion systems. Van der Waals materials hosting
superconducting states are well known, yet nodal monolayer van der Waals
superconductors have remained elusive. Here, using low-temperature scanning
tunneling microscopy (STM) and spectroscopy (STS) experiments, we show that
pristine monolayer 1H-TaS$_2$ realizes a nodal superconducting state. By
including non-magnetic disorder, we drive the nodal superconducting state to a
conventional gapped s-wave state. Furthermore, we observe the emergence of
many-body excitations close to the gap edge, signalling a potential
unconventional pairing mechanism. Our results demonstrate the emergence of
nodal superconductivity in a van der Waals monolayer, providing a building
block for van der Waals heterostructures exploiting unconventional
superconducting states.
Two-dimensional (2D) ferroelectric materials provide a promising platform for
the electrical control of quantum states. In particular, due to their 2D
nature, they are suitable for influencing the quantum states of deposited
molecules via the proximity effect. Here, we report electrically controllable
molecular states in phthalocyanine molecules adsorbed on monolayer
ferroelectric material SnTe. In particular, we demonstrate that the strain and
ferroelectric order in SnTe creates a transition between two distinct orbital
orders in the adsorbed phthalocyanine molecules. By controlling the
polarization of the ferroelectric domain using scanning tunneling microscopy
(STM), we have successfully demonstrated that orbital order can be manipulated
electrically. Our results show how ferroelastic coupling in 2D systems allows
control of molecular states, providing a starting point for ferroelectrically
switchable molecular orbital ordering and ultimately, electrical control of
molecular magnetism.
Van Roosbroeck's equations constitute a versatile tool to determine the
dynamics of electrons under time- and space-dependent perturbations.
Extensively utilized in ordinary semiconductors, their potential to model
devices made from topological materials remains untapped. Here, we adapt van
Roosbroeck's equations to theoretically study the bulk response of a Weyl
semimetal to an ultrafast and spatially localized light pulse in the presence
of a quantizing magnetic field. We predict a transient oscillatory photovoltage
that originates from the chiral anomaly. The oscillations take place at the
plasma frequency (THz range) and are damped by intervalley scattering and
dielectric relaxation. Our results illustrate the ability of van Roosbroeck's
equations to unveil the interplay between electronic band topology and fast
carrier dynamics in microelectronic devices.
Quantum-disordered models provide a versatile platform to explore the
emergence of quantum excitations in many-body systems. The engineering of spin
models at the atomic scale with scanning tunneling microscopy and the local
imaging of excitations with electrically driven spin resonance has risen as a
powerful strategy to image spin excitations in finite quantum spin systems.
Here, focusing on $S=1/2$ lattices as realized by Ti in MgO, we show that
dynamical spin excitations provide a robust strategy to infer the nature of the
underlying Hamiltonian. We show that finite-size interference of the dynamical
many-body spin excitations of a generalized long-range Heisenberg model allows
the underlying spin couplings to be inferred. We show that the spatial
distribution of local spin excitations in Ti islands and ladders directly
correlates with the underlying ground state in the thermodynamic limit. Using a
supervised learning algorithm, we demonstrate that the different parameters of
the Hamiltonian can be extracted by providing the spatially and
frequency-dependent local excitations that can be directly measured by
electrically driven spin resonance with scanning tunneling microscopy. Our
results put forward local dynamical excitations in confined quantum spin models
as versatile witnesses of the underlying ground state, providing an
experimentally robust strategy for Hamiltonian inference in complex real spin
models.
Topological phases play a crucial role in the fundamental physics of
light-matter interaction and emerging applications of quantum technologies.
However, the topological band theory of waveguide QED systems is known to break
down, because the energy bands become disconnected. Here, we introduce a
concept of the inverse energy band and explore analytically topological
scattering in a waveguide with an array of quantum emitters. We uncover a rich
structure of topological phase transitions, symmetric scale-free localization,
completely flat bands, and the corresponding dark Wannier states. Although
bulk-edge correspondence is partially broken because of radiative decay, we
prove analytically that the scale-free localized states are distributed in a
single inverse energy band in the topological phase and in two inverse bands in
the trivial phase. Surprisingly, the winding number of the scattering textures
depends on both the topological phase of inverse subradiant band and the
odevity of the cell number. Our work uncovers the field of the topological
inverse bands, and it brings a novel vision to topological phases in
light-matter interactions.
We present a machine-learning model based on normalizing flows that is
trained to sample from the isobaric-isothermal ensemble. In our approach, we
approximate the joint distribution of a fully-flexible triclinic simulation box
and particle coordinates to achieve a desired internal pressure. This novel
extension of flow-based sampling to the isobaric-isothermal ensemble yields
direct estimates of Gibbs free energies. We test our NPT-flow on monatomic
water in the cubic and hexagonal ice phases and find excellent agreement of
Gibbs free energies and other observables compared with established baselines.
We study $4$-dimensional $SU(N)\times U(1)$ gauge theories with a single
massless Dirac fermion in the $2$-index symmetric/antisymmetric representations
and show that they are endowed with a noninvertible $0$-form $\widetilde
{\mathbb Z}_{2(N\pm 2)}^{\chi}$ chiral symmetry along with a $1$-form $\mathbb
Z_N^{(1)}$ center symmetry. By using the Hamiltonian formalism and putting the
theory on a spatial three-torus $\mathbb T^3$, we construct the non-unitary
gauge invariant operator corresponding to $\widetilde {\mathbb Z}_{2(N\pm
2)}^{\chi}$ and find that it acts nontrivially in sectors of the Hilbert space
characterized by selected magnetic fluxes. When we subject $\mathbb T^3$ to
$\mathbb Z_N^{(1)}$ twists, for $N$ even, in selected magnetic flux sectors,
the algebra of $\widetilde {\mathbb Z}_{2(N\pm 2)}^{\chi}$ and $\mathbb
Z_N^{(1)}$ fails to commute by a $\mathbb Z_2$ phase. We interpret this
noncommutativity as a mixed anomaly between the noninvertible and the $1$-form
symmetries. The anomaly implies that all states in the torus Hilbert space with
the selected magnetic fluxes exhibit a two-fold degeneracy for arbitrary
$\mathbb T^3$ size. The degenerate states are labeled by discrete electric
fluxes and are characterized by nonzero expectation values of condensates. In
an Appendix, we also discuss how to construct the corresponding noninvertible
defect via the ``half-space gauging'' of a discrete one-form magnetic symmetry.
In low-temperature resonant Raman experiments on MoSe$_2$-WSe$_2$
heterobilayers, we identify a hybrid interlayer shear mode (HSM) with an
energy, close to the interlayer shear mode (SM) of the heterobilayers, but with
a much broader, asymmetric lineshape. The HSM shows a pronounced resonance with
the intralayer hybrid trions (HX$^-$) of the MoSe$_2$ and WSe$_2$ layers, only.
No resonance with the neutral intralayer excitons is found. First-principles
calculations reveal a strong coupling of Q-valley states, which are delocalized
over both layers and participate in the HX$^-$, with the SM. This emerging
trion-phonon coupling may be relevant for experiments on gate-controlled
heterobilayers.
We prove that in the chiral limit of the Bistritzer-MacDonald Hamiltonian,
there exist magic angles at which the Hamiltonian exhibits flat bands of
multiplicity four instead of two. We analyze the structure of the Bloch
functions associated with the four bands, the corresponding Chern number, and
show that there exist infinitely many degenerate magic angles for a generic
choice of tunnelling potentials.
For Y$_2$C$_3$ with a superconducting critical temperature (T$_c$) $\sim$18
K, zone-center imaginary optical phonon modes have been found for the
high-symmetry $I$-$43d$ structure due to C dimer wobbling motion and electronic
instability from a flat band near Fermi energy. After lattice distortion to the
more stable lowest symmetry $P1$ structure, these stabilized low-energy phonon
modes with mixed C and Y characters carry a strong electron-phonon coupling to
give arise to the observed sizable T$_c$. Our work shows that compounds with
the calculated dynamical instability should not be simply excluded in
high-throughput search for new phonon-mediated superconductors.
Two common difficulties in the design of topological quantum materials are
that the desired features lie too far from the Fermi level and are spread over
a too large energy range. Doping-induced states at the Fermi level provide a
solution, where non-trivial topological properties are enforced by the
doping-reduced symmetry. To show this, we consider a regular placement of
dopants in a lattice of space group (SG) 176 (P6$\text{}_3$/m), which reduces
the symmetry to SG 143 (P3). Our two- and four-band models feature
symmetry-enforced double Weyl points at $\Gamma$ and A with Chern bands for
$k_z\neq 0,\pi$, Van Hove singularities, nontrivial multiband quantum geometry
due to mixed orbital character, and a singular flat band. The excellent
agreement with density-functional theory (DFT) calculations on copper-doped
lead apatite ('LK-99') provides evidence that minimal topological bands at the
Fermi level can be realized in doped materials.

Date of feed: Wed, 23 Aug 2023 00:30:00 GMT**Search terms: **(topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99) **Superconductivity in a Topological Lattice Model with Strong Repulsion. (arXiv:2308.10935v1 [cond-mat.str-el])**

Rahul Sahay, Stefan Divic, Daniel E. Parker, Tomohiro Soejima, Sajant Anand, Johannes Hauschild, Monika Aidelsburger, Ashvin Vishwanath, Shubhayu Chatterjee, Norman Y. Yao, Michael P. Zaletel

**Coulomb-driven band unflattening suppresses $K$-phonon pairing in moir\'e graphene. (arXiv:2308.10938v1 [cond-mat.supr-con])**

Glenn Wagner, Yves H. Kwan, Nick Bultinck, Steven H. Simon, S.A. Parameswaran

**Experimental demonstration of an integrated on-chip p-bit core utilizing stochastic Magnetic Tunnel Junctions and 2D-MoS$_{2}$ FETs. (arXiv:2308.10989v1 [cond-mat.mes-hall])**

John Daniel, Zheng Sun, Xuejian Zhang, Yuanqiu Tan, Neil Dilley, Zhihong Chen, Joerg Appenzeller

**Stability of a quantum skyrmion: projective measurements and the quantum Zeno effect. (arXiv:2308.11014v1 [quant-ph])**

Fabio Salvati, Mikhail I. Katsnelson, Andrey A. Bagrov, Tom Westerhout

**Strain-Induced Polarization Enhancement in BaTiO$_3$ Core-Shell Nanoparticles. (arXiv:2308.11044v1 [cond-mat.mtrl-sci])**

Eugene A. Eliseev, Anna N. Morozovska, Sergei V. Kalinin, Dean R. Evans

**Exciton Superposition across Moir\'e States in a Semiconducting Moir\'e Superlattice. (arXiv:2308.11054v1 [cond-mat.mes-hall])**

Zhen Lian, Dongxue Chen, Yuze Meng, Xiaotong Chen, Ying Su, Rounak Banerjee, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Chuanwei Zhang, Yong-Tao Cui, Su-Fei Shi

**Nonanalytic Corrections to the Landau Diamagnetic Susceptibility. (arXiv:2308.11057v1 [cond-mat.str-el])**

R. David Mayrhofer, Andrey V. Chubukov

**Photoinduced topological phase transitions in Kitaev-Heisenberg honeycomb ferromagnets with the Dzyaloshinskii-Moriya interaction. (arXiv:2308.11077v1 [cond-mat.str-el])**

Zhengguo Tang, Heng Zhu, Hongchao Shi, Bing Tang

**Theory of a topological analogue of the magnetic bit. (arXiv:2308.11099v1 [cond-mat.mtrl-sci])**

Xinyuan Xu, David Sénéchal, Ion Garate

**Discovery of smectic charge and pair-density-wave orders in topological monolayer 1T$^\prime$-MoTe$_2$. (arXiv:2308.11101v1 [cond-mat.supr-con])**

Li-Xuan Wei, Peng-Cheng Xiao, Fangsen Li, Li Wang, Bo-Yuan Deng, Fang-Jun Cheng, Fa-Wei Zheng, Ning Hao, Ping Zhang, Xu-Cun Ma, Qi-Kun Xue, Can-Li Song

**Ultrastrong Light-Matter Coupling in 2D Metal-Chalcogenates. (arXiv:2308.11108v1 [physics.optics])**

Surendra B. Anantharaman, Jason Lynch, Mariya Aleksich, Christopher E. Stevens, Christopher Munley, Bongjun Choi, Sridhar Shenoy, Thomas Darlington, Arka Majumdar, P. James Shuck, Joshua Hendrickson, J. Nathan Hohman, Deep Jariwala

**Exploring Parity Magnetic Effects through Experimental Simulation with Superconducting Qubits. (arXiv:2308.11115v1 [quant-ph])**

Yu Zhang, Yan-Qing Zhu, Jianwen Xu, Wen Zheng, Dong Lan, Giandomenico Palumbo, Nathan Goldman, Shi-Liang Zhu, Xinsheng Tan, Z.D.Wang, Yang Yu

**Structural, morphological, and magnetic characterizations of (FexMn1-x)2O3 nanocrystals: A comprehensive stoichiometric determination. (arXiv:2308.11128v1 [cond-mat.mtrl-sci])**

John C. Mantilla, Luiz C. C. M. Nagamine, Daniel Cornejo, Renato Cohen, Wesley de Oliveira, Paulo Souza, Sebastião W. da Silva, Fermin F.H. Aragón, Pedro L. Gastelois, Paulo C. Morais, José A.H. Coaquira

**Time-reversal symmetry-breaking flux state in an organic Dirac fermion system. (arXiv:2308.11141v1 [cond-mat.str-el])**

Takao Morinari

**Tuning of Electrical, Magnetic, and Topological Properties of Magnetic Weyl Semimetal Mn$_{3+x}$Ge by Fe doping. (arXiv:2308.11183v1 [cond-mat.mtrl-sci])**

Susanta Ghosh, Achintya Low, Soumya Ghorai, Kalyan Mandal, Setti Thirupathaiah

**Branched flows in active random walks and the formation of ant trail patterns. (arXiv:2308.11232v1 [physics.bio-ph])**

King Hang Mok, Ragnar Fleischmann

**Collective Flows Drive Cavitation in Spinner Monolayers. (arXiv:2308.11280v1 [physics.flu-dyn])**

Zaiyi Shen, Juho S. Lintuvuori

**Nonequilibrium Casimir-Polder Interaction Between Nanoparticles and Substrates Coated with Gapped Graphene. (arXiv:2308.11306v1 [cond-mat.mes-hall])**

Galina L. Klimchitskaya, Constantine C. Korikov, Vladimir M. Mostepanenko, Oleg Yu. Tsybin

**How to identify and characterize strongly correlated topological semimetals. (arXiv:2308.11318v1 [cond-mat.str-el])**

Diana M. Kirschbaum, Monika Lužnik, Gwenvredig Le Roy, Silke Paschen

**A Multi-Technique Study of C2H4 Adsorption on Fe3O4(001). (arXiv:2308.11344v1 [cond-mat.mtrl-sci])**

Lena Puntscher, Panukorn Sombut, Chunlei Wang, Manuel Ulreich, Jiri Pavelec, Ali Rafsanjani-Abbasi, Matthias Meier, Adam Lagin, Martin Setvin, Ulrike Diebold, Cesare Franchini, Michael Schmid, Gareth S. Parkinson

**Skyrmion motion in magnetic anisotropy gradients: Acceleration caused by deformation. (arXiv:2308.11361v1 [cond-mat.mes-hall])**

Ismael Ribeiro de Assis, Ingrid Mertig, Börge Göbel

**Non-Hermitian topological ohmmeter. (arXiv:2308.11367v1 [cond-mat.mes-hall])**

Viktor Könye, Kyrylo Ochkan, Anastasiia Chyzhykova, Jan Carl Budich, Jeroen van den Brink, Ion Cosma Fulga, Joseph Dufouleur

**Hamiltonian learning with real-space impurity tomography in topological moire superconductors. (arXiv:2308.11400v1 [cond-mat.mes-hall])**

Maryam Khosravian, Rouven Koch, Jose L. Lado

**Water Structures Reveal Local Hydrophobicity on the In2O3(111) Surface. (arXiv:2308.11404v1 [cond-mat.mtrl-sci])**

Hao Chen, Matthias A. Blatnik, Christian L. Ritterhoff, Igor Sokolović, Francesca Mirabella, Giada Franceschi, Michele Riva, Michael Schmid, Jan Čechal, Bernd Meyer, Ulrike Diebold, Margareta Wagner

**Adsorption configurations of Co-phthalocyanine on In2O3(111). (arXiv:2308.11423v1 [cond-mat.mtrl-sci])**

Margareta Wagner, Fabio Calcinelli, Andreas Jeindl, Michael Schmid, Oliver T. Hofmann, Ulrike Diebold

**Altermagnetic Orbital Chern Insulator in Twisted MoTe$_{2}$. (arXiv:2308.11454v1 [cond-mat.str-el])**

Feng-Ren Fan, Cong Xiao, Wang Yao

**On Polymer Statistical Mechanics: From Gaussian Distribution to Maxwell-Boltzmann Distribution to Fermi-Dirac Distribution. (arXiv:2308.11482v1 [cond-mat.stat-mech])**

Lixiang Yang

**Combining ultrahigh index with exceptional nonlinearity in resonant transition metal dichalcogenide nanodisks. (arXiv:2308.11504v1 [physics.optics])**

George Zograf, Alexander Yu. Polyakov, Maria Bancerek, Tomasz Antosiewicz, Betul Kucukoz, Timur Shegai

**Salt-assisted vapor-liquid-solid growth of one-dimensional van der Waals materials. (arXiv:2308.11545v1 [cond-mat.mtrl-sci])**

Thang Pham, Kate Reidy, Joachim D. Thomsen, Baoming Wang, Nishant Deshmukh, Michael A. Filler, Frances M. Ross

**Quantifying efficiency of remote excitation for surface enhanced Raman spectroscopy in molecular junctions. (arXiv:2308.11547v1 [cond-mat.mes-hall])**

Shusen Liao, Yunxuan Zhu, Qian Ye, Stephen Sanders, Jiawei Yang, Alessandro Alabastri, Douglas Natelson

**The prototypical organic-oxide interface: intra-molecular resolution of sexiphenyl on In$_2$O$_3$(111). (arXiv:2308.11550v1 [cond-mat.mtrl-sci])**

Margareta Wagner, Jakob Hofinger, Martin Setvín, Lynn A. Boatner, Michael Schmid, Ulrike Diebold

**From the chiral model of TBG to the Bistritzer--MacDonald model. (arXiv:2308.11555v1 [math-ph])**

Simon Becker, Maciej Zworski

**Anomalous minimum and scaling behavior of localization length near an isolated flat band. (arXiv:1509.00881v3 [physics.optics] UPDATED)**

Li Ge

**Evidence of nodal superconductivity in monolayer 1H-TaS$_2$ with hidden order fluctuations. (arXiv:2112.07316v2 [cond-mat.supr-con] UPDATED)**

Viliam Vaňo, Somesh Chandra Ganguli, Mohammad Amini, Linghao Yan, Maryam Khosravian, Guangze Chen, Shawulienu Kezilebieke, Jose L. Lado, Peter Liljeroth

**Control of molecular orbital ordering using a van der Waals monolayer ferroelectric. (arXiv:2207.04245v2 [cond-mat.mtrl-sci] UPDATED)**

Mohammad Amini, Orlando J. Silveira, Viliam Vaňo, Jose L. Lado, Adam S. Foster, Peter Liljeroth, Shawulienu Kezilebieke

**Van Roosbroeck's equations with topological terms: the case of Weyl semimetals. (arXiv:2208.03379v2 [cond-mat.mes-hall] UPDATED)**

Pierre-Antoine Graham, Simon Bertrand, Michaël Bédard, Robin Durand, Ion Garate

**Hamiltonian inference from dynamical excitations in confined quantum magnets. (arXiv:2212.07893v3 [cond-mat.mes-hall] UPDATED)**

Netta Karjalainen, Zina Lippo, Guangze Chen, Rouven Koch, Adolfo O. Fumega, Jose L. Lado

**Topological inverse band theory in waveguide quantum electrodynamics. (arXiv:2301.05481v2 [physics.optics] UPDATED)**

Yongguan Ke, Jiaxuan Huang, Wenjie Liu, Yuri Kivshar, Chaohong Lee

**Estimating Gibbs free energies via isobaric-isothermal flows. (arXiv:2305.13233v2 [physics.comp-ph] UPDATED)**

Peter Wirnsberger, Borja Ibarz, George Papamakarios

**Noninvertible anomalies in $SU(N)\times U(1)$ gauge theories. (arXiv:2305.14425v2 [hep-th] UPDATED)**

Mohamed M. Anber, Erich Poppitz

**Emergent Trion-Phonon Coupling in Atomically-Reconstructed MoSe$_2$-WSe$_2$ Heterobilayers. (arXiv:2306.01483v2 [cond-mat.mes-hall] UPDATED)**

Sebastian Meier, Yaroslav Zhumagulov, Matthias Dietl, Philipp Parzefall, Michael Kempf, Johannes Holler, Philipp Nagler, Paulo E. Faria Junior, Jaroslav Fabian, Tobias Korn, Christian Schüller

**Degenerate flat bands in twisted bilayer graphene. (arXiv:2306.02909v2 [math-ph] UPDATED)**

Simon Becker, Tristan Humbert, Maciej Zworski

**Imaginary phonon modes and phonon-mediated superconductivity in Y2C3. (arXiv:2308.00201v2 [cond-mat.supr-con] UPDATED)**

Niraj K. Nepal, Paul C. Canfield, Lin-Lin Wang

**Minimal model for double Weyl points, multiband quantum geometry, and singular flat band inspired by LK-99. (arXiv:2308.03751v2 [cond-mat.mes-hall] UPDATED)**

Moritz M. Hirschmann, Johannes Mitscherling

Found 13 papers in prb It is now widely believed that $p$-wave superfluidity is the key to generate a novel critical phase in the non-Abelian Aubry-André-Harper model. However, we here establish that this belief is incorrect. In this work, we systemically investigate the phase transition of a non-Abelian quasiperiodic mos… Intrinsic topological superconducting materials are exotic and vital to develop the next-generation topological superconducting devices, topological quantum calculations, and quantum information technologies. Here, we predict the topological and nodal superconductivity of NiAs-type $M\mathrm{S}$ $(M… Despite extensive existing studies, a complete understanding of the role of disorder in affecting the physical properties of two-dimensional Dirac fermionic systems remains a standing challenge, largely due to obstacles encountered in treating multiple scattering events for such inherently strong sc… In recent experimental and theoretical studies of graphene, disorder scattering processes have been suggested to play an important role in its electronic and transport properties. In a preceding paper, it has been shown that the nonperturbative momentum-space Lanczos method is able to accurately des… An underestimation of the fundamental band gap values by the density functional theory within the local density approximation and associated approaches is a well-known challenge of Recurrent neural networks (RNNs), originally developed for natural language processing, hold great promise for accurately describing strongly correlated quantum many-body systems. Here, we employ two-dimensional RNNs to investigate two prototypical quantum many-body Hamiltonians exhibiting topologic… Utilizing a low-temperature scanning-tunneling microscope, we construct Fe kagome-honeycomb lattices on Ag(111) and investigate their lattice parameter dependent electronic properties. The probed spectra exhibit the characteristic lattice peaks, which gradually merge and form a flat-band peak with d… We consider a superlattice formed by tunnel-connected identical holes, periodically placed in a two-dimensional topological insulator. We study tunneling transport through helical edges of these holes and demonstrate that the band structure of such helical crystal can be controlled by both gate elec… Utilizing the exceptional characteristics of two-dimensional (2D) materials for solid-state electronic devices presents an appealing strategy that could potentially address the need to prolong Moore's law. Evidently, the prevailing fraction of technically viable materials, which have already been su… Exciton-polaritons are bosoniclike elementary excitations in semiconductors, which have been recently shown to display large occupancy of topologically protected polariton bound states in the continuum in suitably engineered photonic lattices [V. Ardizzone With first-principles calculations and theoretical models, we reveal the connection between stacking order, film thickness, and topological behaviors in layered ${M}_{2}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{5} (M=\mathrm{Ge},\mathrm{Sn},\mathrm{Pb})$ films. We find that single-layer ${M}_{2}{\mathrm{Bi}}_… Majorana zero modes (MZMs) emerge as edge states in topological superconductors and are promising for topological quantum computation, but their detection has so far been elusive. Here we show that non-Hermiticity can be used to obtain dramatically more robust MZMs. The enhanced properties appear as… Searching for topological insulators in solids is one of the main issues of modern condensed-matter physics since robust gapless edge or surface states of the topological insulators can be used as building blocks of next-generation devices. Enhancing spin-orbit couplings is a promising way to realiz…

Date of feed: Wed, 23 Aug 2023 03:16:59 GMT**Search terms: **(topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99) **Phase transition of a non-Abelian quasiperiodic mosaic lattice model with $p$-wave superfluidity**

Jincui Zhao, Yujia Zhao, Ji-Guo Wang, Yueqing Li, and Xiao-Dong Bai

Author(s): Jincui Zhao, Yujia Zhao, Ji-Guo Wang, Yueqing Li, and Xiao-Dong Bai

[Phys. Rev. B 108, 054204] Published Tue Aug 22, 2023

**Higher-order topological and nodal superconducting transition-metal sulfides $M\mathrm{S} (M=\mathrm{Nb} \text{and} \mathrm{Ta})$**

Yipeng An, Juncai Chen, Yong Yan, Jinfeng Wang, Yinong Zhou, Zhengxuan Wang, Chunlan Ma, Tianxing Wang, Ruqian Wu, and Wuming Liu

Author(s): Yipeng An, Juncai Chen, Yong Yan, Jinfeng Wang, Yinong Zhou, Zhengxuan Wang, Chunlan Ma, Tianxing Wang, Ruqian Wu, and Wuming Liu

[Phys. Rev. B 108, 054519] Published Tue Aug 22, 2023

**Disorder effects on the quasiparticle and transport properties of two-dimensional Dirac fermionic systems**

Bo Fu, Yanru Chen, Weiwei Chen, Wei Zhu, Ping Cui, Qunxiang Li, Zhenyu Zhang, and Qinwei Shi

Author(s): Bo Fu, Yanru Chen, Weiwei Chen, Wei Zhu, Ping Cui, Qunxiang Li, Zhenyu Zhang, and Qinwei Shi

[Phys. Rev. B 108, 064207] Published Tue Aug 22, 2023

**Quasiparticle and transport properties of disordered bilayer graphene**

Yanru Chen, Bo Fu, Jinrong Xu, Qinwei Shi, Ping Cui, and Zhenyu Zhang

Author(s): Yanru Chen, Bo Fu, Jinrong Xu, Qinwei Shi, Ping Cui, and Zhenyu Zhang

[Phys. Rev. B 108, 064208] Published Tue Aug 22, 2023

*Ab initio* overestimation of the topological region in Eu-based compounds

Giuseppe Cuono, Raghottam M. Sattigeri, Carmine Autieri, and Tomasz Dietl

Author(s): Giuseppe Cuono, Raghottam M. Sattigeri, Carmine Autieri, and Tomasz Dietl*ab initio* electronic structure computations. Motivated by recent optical experiments [D. Santos-Cottin *et al.*, arXiv:2…

[Phys. Rev. B 108, 075150] Published Tue Aug 22, 2023

**Investigating topological order using recurrent neural networks**

Mohamed Hibat-Allah, Roger G. Melko, and Juan Carrasquilla

Author(s): Mohamed Hibat-Allah, Roger G. Melko, and Juan Carrasquilla

[Phys. Rev. B 108, 075152] Published Tue Aug 22, 2023

**Experimental demonstration of the band compression effect in engineered kagome-honeycomb lattices**

R. G. Yan, T. Z. Ji, W. L. Fan, Z. X. Zhang, H. T. Li, L. Sun, B. F. Miao, G. Chen, and H. F. Ding

Author(s): R. G. Yan, T. Z. Ji, W. L. Fan, Z. X. Zhang, H. T. Li, L. Sun, B. F. Miao, G. Chen, and H. F. Ding

[Phys. Rev. B 108, 075153] Published Tue Aug 22, 2023

**Tunable helical crystals**

R. A. Niyazov, D. N. Aristov, and V. Yu. Kachorovskii

Author(s): R. A. Niyazov, D. N. Aristov, and V. Yu. Kachorovskii

[Phys. Rev. B 108, 075424] Published Tue Aug 22, 2023

**Origin of strain tunability in flat valence band and ultrahigh shear piezoelectricity in superflexible non–van der Waals graphitic $\mathrm{Sc}X$ monolayers ($X=\mathrm{P}$, As, Sb)**

Harshita Seksaria, Arneet Kaur, and Abir De Sarkar

Author(s): Harshita Seksaria, Arneet Kaur, and Abir De Sarkar

[Phys. Rev. B 108, 075426] Published Tue Aug 22, 2023

**Theory of exciton-polariton condensation in gap-confined eigenmodes**

Davide Nigro and Dario Gerace

Author(s): Davide Nigro and Dario Gerace*et al.*, Nature (London) **605**, 447 (2022)], …

[Phys. Rev. B 108, 085305] Published Tue Aug 22, 2023

**Stacking-layer-tuned topological phases in ${M}_{2}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{5} (M=\mathrm{Ge},\mathrm{Sn},\mathrm{Pb})$ films**

Yue Li, Yujin Jia, Bao Zhao, Hairui Bao, Hao Huan, Hongming Weng, and Zhongqin Yang

Author(s): Yue Li, Yujin Jia, Bao Zhao, Hairui Bao, Hao Huan, Hongming Weng, and Zhongqin Yang

[Phys. Rev. B 108, 085428] Published Tue Aug 22, 2023

**Topological superconductivity enhanced by exceptional points**

R. Arouca, Jorge Cayao, and Annica M. Black-Schaffer

Author(s): R. Arouca, Jorge Cayao, and Annica M. Black-Schaffer

[Phys. Rev. B 108, L060506] Published Tue Aug 22, 2023

**Correlated Zak insulator in organic antiferromagnets**

Takahiro Misawa and Makoto Naka

Author(s): Takahiro Misawa and Makoto Naka

[Phys. Rev. B 108, L081120] Published Tue Aug 22, 2023

Found 1 papers in prl The Landau-Ginzburg-Wilson theory of phase transitions precludes a continuous transition between two phases that spontaneously break distinct symmetries. However, quantum mechanical effects can intertwine the symmetries, giving rise to an exotic phenomenon called deconfined quantum criticality (DQC)…

Date of feed: Wed, 23 Aug 2023 03:17:00 GMT**Search terms: **(topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99) **Landau-Forbidden Quantum Criticality in Rydberg Quantum Simulators**

Jong Yeon Lee, Joshua Ramette, Max A. Metlitski, Vladan Vuletić, Wen Wei Ho, and Soonwon Choi

Author(s): Jong Yeon Lee, Joshua Ramette, Max A. Metlitski, Vladan Vuletić, Wen Wei Ho, and Soonwon Choi

[Phys. Rev. Lett. 131, 083601] Published Tue Aug 22, 2023

Found 1 papers in sci-rep Scientific Reports, Published online: 22 August 2023; doi:10.1038/s41598-023-40864-5**Search terms: **(topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99) **Author Correction: Demonstration of cross reaction in hybrid graphene oxide/tantalum dioxide guided mode resonance sensor for selective volatile organic compound**

Sakoolkan Boonruang

Found 1 papers in nat-comm **Search terms: **(topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99) **Topological soliton molecule in quasi 1D charge density wave**

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