Found 32 papers in cond-mat The topology of electronic and phonon band structures of graphene is well
studied and known to exhibit a Dirac cone at the K point of the Brillouin zone.
Here, we applied inelastic x-ray scattering (IXS) along with $\textit{ab
initio}$ calculations to investigate phonon topology in graphite, the 3D
analogue of graphene. We identified a pair of modes that form a very weakly
gapped linear anticrossing at the K point that can be essentially viewed as a
Dirac cone approximant. The IXS intensity in the vicinity of the quasi-Dirac
point reveals a harmonic modulation of the phonon spectral weight above and
below the Dirac energy, which was previously proposed as an experimental
fingerprint of the nontrivial topology. We illustrate how the topological
winding of IXS intensity can be understood in terms of atomic displacements,
and highlight that the intensity winding is not in fact sensitive in telling
quasi- and true Dirac points apart.
Characteristic classes, which are abstract topological invariants associated
with vector bundles, have become an important notion in modern physics with
surprising real-world consequences. As a representative example, the incredible
properties of topological insulators, which are insulators in their bulk but
conductors on their surface, can be completely characterized by a specific
characteristic class associated with their electronic band structure, the first
Chern class. Given their importance to next generation computing and the
computational challenge of calculating them using first-principles approaches,
there is a need to develop machine learning approaches to predict the
characteristic classes associated with a material system. To aid in this
program we introduce the {\emph{Haldane bundle dataset}}, which consists of
synthetically generated complex line bundles on the $2$-torus. We envision this
dataset, which is not as challenging as noisy and sparsely measured real-world
datasets but (as we show) still difficult for off-the-shelf architectures, to
be a testing ground for architectures that incorporate the rich topological and
geometric priors underlying characteristic classes.
The bulk-boundary correspondence is a hallmark feature of topological phases
of matter. Nonetheless, our understanding of the correspondence remains
incomplete for phases with intrinsic topological order, and is nearly entirely
lacking for more exotic phases, such as fractons. Intriguingly, for the former,
recent work suggests that bulk topological order manifests in a non-local
structure in the boundary Hilbert space; however, a concrete understanding of
how and where this perspective applies remains limited. Here, we provide an
explicit and general framework for understanding the bulk-boundary
correspondence in Pauli topological stabilizer codes. We show -- for any
boundary termination of any two-dimensional topological stabilizer code -- that
the boundary Hilbert space cannot be realized via local degrees of freedom, in
a manner precisely determined by the anyon data of the bulk topological order.
We provide a simple method to compute this "obstruction" using a well-known
mapping to polynomials over finite fields. Leveraging this mapping, we
generalize our framework to fracton models in three-dimensions, including both
the X-Cube model and Haah's code. An important consequence of our results is
that the boundaries of topological phases can exhibit emergent symmetries that
are impossible to otherwise achieve without an unrealistic degree of fine
tuning. For instance, we show how linear and fractal subsystem symmetries
naturally arise at the boundaries of fracton phases.
We explore the decoherence of the gapless/critical boundary of a topological
order, through interactions with the bulk reservoir of "ancilla anyons." We
take the critical boundary of the $2d$ toric code as an example. The intrinsic
nonlocal nature of the anyons demands the strong and weak symmetry condition
for the ordinary decoherence problem be extended to the strong or weak gauge
invariance conditions. We demonstrate that in the $\textit{doubled}$ Hilbert
space, the partition function of the boundary is mapped to two layers of the
$2d$ critical Ising model with an inter-layer line defect that depends on the
species of the anyons causing the decoherence. The line defects associated with
the tunneling of bosonic $e$ and $m$ anyons are relevant, and result in
long-range correlations for either the $e$ or $m$ anyon respectively on the
boundary in the doubled Hilbert space. In contrast, the defect of the $f$ anyon
is marginal and leads to a line of fixed points with varying effective central
charges, and power-law correlations having continuously varying scaling
dimensions. We also demonstrate that decoherence-analogues of Majorana zero
modes are localized at the spatial interface of the relevant $e$ and $m$ anyon
decoherence channels, which leads to a universal logarithmic scaling of the
R\'enyi entropy of the boundary.
We theoretically investigate the steady-state transmission of continuous
terahertz (THz) wave across a freestanding ferroelectric slab. Based on the
Landau-Ginzburg-Devonshire theory of ferroelectrics and the coupled equations
of motion for polarization and electromagnetic (EM) waves, we derive the
analytical expressions of the frequency- and thickness-dependent dielectric
susceptibility and transmission coefficient at the thin slab limit in the
harmonic excitation regime. When the slab thickness is much smaller than the
THz wavelength in the ferroelectric, the analytical predictions agree well with
the numerical simulations from a dynamical phase-field model that incorporates
the coupled dynamics of strain, polarization, and EM wave in multiphase
systems. At larger thicknesses, the transmission is mainly determined by the
frequency-dependent attenuation of THz waves in the ferroelectric and the
formation of a standing polarization/THz wave. Our results advance the
understanding of the interaction between THz wave and ferroelectrics and
suggest the potential of exploiting ferroelectrics to achieve
low-heat-dissipation, nonvolatile voltage modulation of THz transmission for
high-data-rate wireless communication.
Advanced microelectronics in the future may require semiconducting channel
materials beyond silicon. Two-dimensional (2D) semiconductors, characterized by
their atomically thin thickness, hold immense promise for high-performance
electronic devices at the nanometer scale with lower heat dissipation. One
challenge for achieving high-performance 2D semiconductor field effect
transistors (FET), especially for p-type materials, is the high electrical
contact resistance present at the metal-semiconductor interface. In
conventional bulk semiconductors, low resistance ohmic contact is realized
through heavy substitutional doping with acceptor or donor impurities at the
contact region. The strategy of substitutional doping, however, does not work
for p-type 2D semiconductors such as monolayer tungsten diselenide (WSe$_2$).In
this study, we developed highly efficient charge-transfer doping with
WSe$_2$/$\alpha$-RuCl$_3$ heterostructures to achieve low-resistance ohmic
contact for p-type WSe$_2$ transistors. We show that a hole doping as high as
3$\times$10$^{13}$ cm$^{-2}$ can be achieved in the WSe$_2/\alpha$-RuCl$_3$
heterostructure due to its type-III band alignment. It results in an Ohmic
contact with resistance lower than 4 k Ohm $\mu$m at the p-type monolayer
WSe$_2$/metal junction. at room temperature. Using this low-resistance contact,
we demonstrate high-performance p-type WSe$_2$ transistors with a saturation
current of 35 $\mu$A$\cdot$ $\mu$m$^{-1}$ and an I$_{ON}$/I$_{OFF}$ ratio
exceeding 10$^9$ It could enable future microelectronic devices based on 2D
semiconductors and contribute to the extension of Moore's law.
We investigate the Goos-H\"{a}nchen shifts in reflection for a light beam
within a graphene structure, utilizing the Fizeau drag effect induced by its
massless Dirac electrons in incident light. The magnitudes of spatial and
angular shifts for a light beam propagating against the direction of drifting
electrons are significantly enhanced, while shifts for a beam co-propagating
with the drifting electrons are suppressed. The Goos-H\"{a}nchen shifts exhibit
augmentation with increasing drift velocities of electrons in graphene. The
impact of incident wavelength on the angular and spatial shifts in reflection
is discussed. Furthermore, the study highlights the crucial roles of the
density of charged particles in graphene, the particle relaxation time, and the
thickness of the graphene in manipulating the drag-affected Goos-H\"{a}nchen
shifts. This investigation offers valuable insights for efficiently guiding
light in graphene structures under the influence of the Fizeau drag effect.
We consider the hydrodynamic flow of an electron fluid in a channel formed in
a two-dimensional electron gas (2DEG) with no-slip boundary conditions. To
generate vorticity in the fluid the flow is influenced by an array of
micromagnets on the top of 2DEG. We analyse the viscous boundary layer and
demonstrate anti-Poiseuille behaviour in this region. Furthermore we predict a
longitudinal Hall effect, where a periodic magnetic field generates a voltage
modulation in the direction of transport. From the experimental point of view
we propose a method for a precise measurements of the properties of different
electron fluids. The results are applicable to graphene away from the charge
neutrality point and to semiconductors.
Neuromorphic devices have gained significant attention as potential building
blocks for the next generation of computing technologies owing to their ability
to emulate the functionalities of biological nervous systems. The essential
components in artificial neural network such as synapses and neurons are
predominantly implemented by dedicated devices with specific functionalities.
In this work, we present a gate-controlled transition of neuromorphic functions
between artificial neurons and synapses in monolayer graphene transistors that
can be employed as memtransistors or synaptic transistors as required. By
harnessing the reliability of reversible electrochemical reactions between C
atoms and hydrogen ions, the electric conductivity of graphene transistors can
be effectively manipulated, resulting in high on/off resistance ratio,
well-defined set/reset voltage, and prolonged retention time. Furthermore, the
gate-controlled linear response of set/reset voltage in memtransistors
facilitates a more versatile way to regulate the synaptic weight and neural
spiking. Overall, the on-demand switching of neuromorphic functions in a single
graphene transistor provides a promising opportunity to develop adaptive neural
networks for the upcoming era of artificial intelligence and machine learning.
The study of open-shell nanographenes has relied on a paradigm where spins
are the only low-energy degrees of freedom. Here we show that some
nanographenes can host low-energy excitations that include strongly coupled
spin and orbital degrees of freedom. The key ingredient is the existence of
orbital degeneracy, as a consequence of leaving the benzenoid/half-filling
scenario. We analyze the case of nitrogen-doped triangulenes, using both
density-functional theory and Hubbard model multiconfigurational and
random-phase approximation calculations. We find a rich interplay between
orbital and spin degrees of freedom that confirms the need to go beyond the
spin-only paradigm, opening a new venue in this field of research.
We report the existence of previously unreported magnetic modes with
record-high magnetic Purcell factors in topological-insulator nanospheres.
Focusing on Bi$_{2}$Se$_{3}$, and based on full electromagnetic Mie theory, we
find magnetic modes arising from the surface current on the conductive surface
of the topological insulator due to the existence of delocalized surface
states. These currents are induced by electrons in the topologically protected
states within the Dirac cone. Furthermore, we demonstrate that the Dirac
plasmon polaritons resulting from the interaction between THz photons and Dirac
electrons dramatically influence both the electric and the magnetic transitions
of quantum emitters placed near Bi$_2$Se$_3$ nanospheres, providing
significantly enhanced Purcell factors and entering the strong-coupling regime.
These findings indicate that Bi$_{2}$Se$_{3}$ nanospheres exhibit a rich
optical response, stemming from both bulk and topologically protected surface
states, making them promising candidates for enhancing strong light--matter
interactions in the fields of nanophotonics and THz technologies.
We study nonequilibrium dynamics of relativistic $N$-component scalar field
theories in Minkowski space-time in a classical-statistical regime, where
typical occupation numbers of modes are much larger than unity. In this
strongly correlated system far from equilibrium, the role of different
phenomena such as nonlinear wave propagation and defect dynamics remains to be
clarified. We employ persistent homology to infer topological features of the
nonequilibrium many-body system for different numbers of field components $N$
via a hierarchy of cubical complexes. Specifically, we show that the persistent
homology of local energy density fluctuations can give rise to signatures of
self-similar scaling associated with topological defects, distinct from the
scaling behaviour of nonlinear wave modes. This contributes to the systematic
understanding of the role of topological defects for far-from-equilibrium time
evolutions of nonlinear many-body systems.
The organization of water molecules and ions between charged mineral surfaces
determines the stability of colloidal suspensions and the strength of
phase-separated particulate gels. In this article we assemble a density
functional that measures the free energy due to the interaction of water
molecules and ions near electric double layers. The model accounts for the
finite size of the particles using fundamental measure theory, hydrogen-bonding
between water molecules using Wertheim's statistical association theory,
long-range dispersion interactions using Barker and Henderson's high
temperature expansion, electrostatic correlations using a functionalized
mean-spherical approximation, and Coulomb forces through the Poisson equation.
These contributions are shown to produce highly correlated structures, aptly
rendering the layering of counter-ions and co-ions at highly charged surfaces,
and permitting the solvation of ions and surfaces to be measured by a
combination of short-ranged association and long-ranged attraction. The model
is tested in a planar geometry near soft, charged surfaces to reproduce the
structure of water near graphene and mica. For mica surfaces, explicitly
representing the density of the outer oxygen layer of the exposed silica
tetrahedra in the domain permits water molecules to hydrogen-bind to the
surface. When electrostatic interactions are included, water molecules assume a
hybrid character, being accounted for implicitly in the dielectric constant but
explicitly otherwise. The disjoining pressure between approaching like-charged
surfaces is calculated, demonstrating the model's ability to probe pressure
oscillations that arise during the expulsion of ions and water layers from the
interfacial gap, and predict the strong inter-attractive stresses that form at
narrow interfacial spacing when the surface charge is overscreened.
We theoretically show quasiparticles-driven thermal diode effect (TDE) in an
inversion symmetry-broken (ISB) Weyl superconductor (WSC)-Weyl semimetal
(WSM)-WSC Josephson junction. A Zeeman field perpendicular to the WSM region of
the thermally-biased Weyl Josephson junction (WJJ) induces an asymmetry between
the forward and reverse thermal currents, which is responsible for the TDE.
Most interestingly, we show that the sign and magnitude of the thermal diode
rectification coefficient is highly tunable by the superconducting phase
difference and external Zeeman field, and also strongly depends on the junction
length. The tunability of the rectification, particularly, the sign changing
behavior associated with higher rectification enhances the potential of our WJJ
thermal diode to use as functional switching components in thermal devices.
We employ quadratic-response Kubo formulas to investigate the nonlinear
magnetotransport in bilayers composed of a topological insulator and a magnetic
insulator, and predict both unidirectional magnetoresistance and nonlinear
planar Hall effects driven by interfacial disorder and spin-orbit scattering.
These effects exhibit strong dependencies on the Fermi energy relative to the
strength of the exchange interaction between the spins of Dirac electrons and
the interfacial magnetization. In particular, as the Fermi energy becomes
comparable to the exchange energy, the nonlinear magnetotransport coefficients
can be greatly amplified and their dependencies on the magnetization
orientation deviate significantly from conventional sinusoidal behavior. These
findings may not only deepen our understanding of the origin of nonlinear
magnetotransport in magnetic topological systems but also open new pathways to
probe the Fermi and exchange energies via transport measurements.
Collisions between electrons and holes can dominate the carrier scattering in
clean graphene samples in the vicinity of charge neutrality point. While
electron-hole limited resistance in pristine gapless graphene is well-studied,
its evolution with induction of band gap $E_g$ is less explored. Here, we
derive the functional dependence of electron-hole limited resistance of gapped
graphene $\rho_{eh}$ on the ratio of gap and thermal energy $E_g/kT$. At low
temperatures and large band gaps, the resistance grows linearly with $E_g/kT$,
and possesses a minimum at $E_g \approx 2.5 kT$. This contrast to the Arrhenius
activation-type behaviour for intrinsic semiconductors. Introduction of
impurities restores the Arrhenius law for resistivity at low temperatures
and/or high doping densities. The hallmark of electron-hole collision effects
in graphene resistivity at charge neutrality is the crossover between
exponential and power-law resistivity scalings with temperature.
Emerging colloidal quantum dot (cQD) photodetectors currently challenge
established state-of-the-art infrared photodetectors in response speed,
spectral tunability, simplicity of solution processable fabrication, and
integration onto curved or flexible substrates. Hybrid phototransistors based
on 2D materials and cQDs, in particular, are promising due to their inherent
photogain enabling direct photosignal enhancement. The photogain is sensitive
to both, measurement conditions and photodetector geometry. This makes the
cross-comparison of devices reported in the literature rather involved. Here,
the effect of device length L and width W scaling to subwavelength dimensions
(sizes down to 500 nm) on the photoresponse of graphene-PbS cQD
phototransistors was experimentally investigated. Photogain and responsivity
were found to scale with 1/LW, whereas the photocurrent and specific
detectivity were independent of geometrical parameters. The measurements were
performed at scaled bias voltage conditions for comparable currents. Contact
effects were found to limit the photoresponse for devices with L < 3 {\mu}m.
The relation of gate voltage, bias current, light intensity, and frequency on
the photoresponse was investigated in detail, and a photogating efficiency to
assess the cQD-graphene interface is presented. In particular, the specific
detectivity values in the range between 10^8 to 10^9 Jones (wavelength of 1550
nm, frequency 6 Hz, room temperature) were found to be limited by the charge
transfer across the photoactive interface.
Heterostructures of topological insulator Bi$_2$Se$_3$ on transition metal
dichalcogenides (TMDCs) offer a new materials platform for studying novel
quantum states by exploiting the interplay among topological orders, charge
orders and magnetic orders. The diverse interface attributes, such as material
combination, charge re-arrangement, defect and strain, can be utilized to
manipulate the quantum properties of this class of materials. Recent
experiments of Bi$_2$Se$_3$/NbSe$_2$ heterostructures show signatures of strong
Rashba band splitting due to the presence of a BiSe buffer layer, but the
atomic level mechanism is not fully understood. We conduct first-principles
studies of the Bi$_2$Se$_3$/BiSe/TMDC heterostructures with five different TMDC
substrates (1T phase VSe$_2$, MoSe$_2$, TiSe$_2$, and 2H phase NbSe$_2$,
MoSe$_2$). We find significant charge transfer at both BiSe/TMDC and
Bi$_2$Se$_3$/BiSe interfaces driven by the work function difference, which
stabilizes the BiSe layer as an electron donor and creates interface dipole.
The electric field of the interface dipole breaks the inversion symmetry in the
Bi$_2$Se$_3$ layer, leading to the giant Rashba band splitting in two quintuple
layers and the recovery of the Dirac point in three quintuple layers, with the
latter otherwise only occurring in thicker samples with at least six
Bi$_2$Se$_3$ quintuple layers. Besides, we find that strain can significantly
affect the charge transfer at the interfaces. Our study presents a promising
avenue for tuning topological properties in heterostructures of two-dimensional
materials, with potential applications in quantum devices.
In the unconventional superconductor Sr$_2$RuO$_4$, uniaxial stress along the
$[100]$ direction tunes the Fermi level through a Van Hove singularity (VHS) in
the density of states, causing a strong enhancement of the superconducting
critical temperature $T_\textrm{c}$. Here, we report measurements of the London
penetration depth $\lambda$ as this tuning is performed. We find that the
zero-temperature superfluid density, here defined as $\lambda(0)^{-2}$,
increases by $\sim$15%, with a peak that coincides with the peak in
$T_\textrm{c}$. We also find that the low temperature form of $\lambda(T)$ is
quadratic over the entire strain range. Using scanning tunneling microscopy, we
find that the gap increases from $\Delta_0 \approx 350~\mu$eV in unstressed
Sr$_2$RuO$_4$ to $\Delta_0 \approx 600~\mu$eV in a sample strained to near the
peak in $T_c$. With a nodal order parameter, an increase in the superconducting
gap could bring about an increase in the superfluid density through reduced
sensitivity to defects and through reduced non-local effects in the Meissner
screening. Our data indicate that tuning to the VHS increases the gap
throughout the Brillouin zone, and that non-local effects are likely more
important than reduced scattering.
Realizing direct-bandgap quantum dots working within the deep-ultraviolet
frequency is highly desired for electro-optical and biomedical applications
while remaining challenging. In this work, we combine the first-principles
many-body perturbation theory and effective Hamiltonian approximation to
propose the realization of arrays of deep-ultraviolet excitonic quantum dots in
twisted bilayer hexagonal boron nitride. The effective quantum confinement of
excitons can reach ~400 meV within small twisting angles, which is about four
times larger than those observed in twisted semiconducting transitional metal
dichalcogenides. Especially because of enhanced electron-hole attraction, those
excitons will accumulate via the so-call exciton funnel effect to the
direct-bandgap regime, giving the possibility to better luminescence
performance and manipulating coherent arrays of deep-ultraviolet quantum dots.
Atomic-scale defect detection is shown in scanning tunneling microscopy
images of single crystal WSe2 using an ensemble of U-Net-like convolutional
neural networks. Standard deep learning test metrics indicated good detection
performance with an average F1 score of 0.66 and demonstrated ensemble
generalization to C-AFM images of WSe2 and STM images of MoSe2. Defect
coordinates were automatically extracted from defect detections maps showing
that STM image analysis enhanced by machine learning can be used to
dramatically increase sample characterization throughput.
We present the dynamical spin structure factor of the antiferromagnetic
spin-$\frac{1}{2}$ $J_1-J_2$ Heisenberg model on a triangular lattice obtained
from large-scale matrix-product state simulations. The high frustration due to
the combination of antiferromagnetic nearest and next-to-nearest neighbour
interactions yields a rich phase diagram. We resolve the low-energy excitations
both in the $120^{\circ}$-ordered phase and in the putative spin liquid phase
at $J_2/J_1 = 0.125$. In the ordered phase, we observe an avoided decay of the
lowest magnon-branch, demonstrating the robustness of this phenomenon in the
presence of gapless excitations. Our findings in the spin-liquid phase chime
with the field-theoretical predictions for a gapless Dirac spin liquid, in
particular the picture of low-lying monopole excitations at the corners of the
Brillouin zone. We comment on possible practical difficulties of distinguishing
proximate liquid and solid phases based on the dynamical structure factor.
We revisit the Hofstadter butterfly for a subset of topologically trivial
Bloch bands arising from a continuum free electron Hamiltonian in a periodic
lattice potential. We employ the recently developed procedure -- which was
previously used to analyze the case of topologically non-trivial bands
[\href{https://journals.aps.org/prb/abstract/10.1103/PhysRevB.106.L121111}{Phys.
Rev. B \textbf{106}, L121111 (2022)}] -- to construct the finite field Hilbert
space from the zero-field hybrid Wannier basis states. Such states are Bloch
extended along one direction and exponentially localized along the other. The
method is illustrated for square and triangular lattice potentials and is shown
to reproduce all the main features of the Hofstadter spectrum obtained from a
numerically exact Landau level expansion method.
In the regime when magnetic length is much longer than the spatial extent of
the hybrid Wannier state in the localized direction we recover the well known
Harper equation. Because the method applies to both topologically trivial and
non-trivial bands, it provides an alternative and efficient approach to moir\'e
materials in magnetic field.
We analyze the probability density distribution in a topological insulator
slab of finite thickness, where the bulk and surface states are allowed to
hybridize. By using an effective continuum Hamiltonian approach as a
theoretical framework, we analytically obtained the wave functions for each
state near the $\Gamma$-point. Our results reveal that, under particular
combinations of the hybridized bulk and surface states, the spatial symmetry of
the electronic probability density with respect to the center of the slab can
be spontaneously broken. This symmetry breaking arises as a combination of the
parity of the solutions, their spin projection, and the material constants.
Soft magnetic dots in the form of thin rings have unique topological
properties. They can be in a vortex state with no vortex core. Here, we study
the magnon modes of such systems both analytically and numerically. In an
external magnetic field, magnetic rings are characterized by easy-cone
magnetization and shows a giant splitting of doublets for modes with the
opposite value of the azimuthal mode quantum number. The effect of the
splitting can be refereed as a magnon analog of the topology-induced
Aharonov-Bohm effect. For this we develop an analytical theory to describe the
non-monotonic dependence of the mode frequencies on the azimuthal mode number,
influenced by the balance between the local exchange and non-local dipole
interactions.
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.
Competing measurements alone can give rise to distinct phases characterized
by entanglement entropy$\unicode{x2013}$such as the volume law phase,
symmetry-breaking (SB) phase, and symmetry-protected topological (SPT)
phase$\unicode{x2013}$that can only be discerned through quantum trajectories,
making them challenging to observe experimentally. In another burgeoning area
of research, recent studies have demonstrated that steering can give rise to
additional phases within quantum circuits. In this work, we show that new
phases can appear in measurement-only quantum circuit with steering. Unlike
conventional steering methods that rely solely on local information, the
steering scheme we introduce requires the circuit's structure as an additional
input. These steering induced phases are termed as "informative" phases. They
are distinguished by the intrinsic dimension of the bitstrings measured in each
circuit run, making them substantially easier to detect in experimental setups.
We explicitly show this phase transition by numerical simulation in three
circuit models that are previously well-studied: projective transverse field
Ising model, lattice gauge-Higgs model and XZZX model. When the informative
phase coincides with the SB phase, our steering mechanism effectively serves as
a "pre-selection" routine, making the SB phase more experimentally accessible.
Additionally, an intermediate phase may manifest, where a discrepancy arises
between the quantum information captured by entanglement entropy and the
classical information conveyed by bitstrings. Our findings demonstrate that
steering not only adds theoretical richness but also offers practical
advantages in the study of measurement-only quantum circuits.
Nodal-line semimetals are commonly believed to exist in $\mathcal{PT}$
symmetric or mirror-rotation symmetric systems. Here, we find a flux-induced
parameter-dimensional second-order nodal-line semimetal (SONLS) in a
two-dimensional system without $\mathcal{PT}$ and mirror-rotation symmetries.
It has coexisting hinge Fermi arcs and drumhead surface states. Meanwhile, we
discover a flux-induced second-order topological insulator (SOTI). We then
propose a Floquet engineering scheme to create exotic parameter-dimensional
hybrid-order nodal-line semimetals with abundant nodal-line structures and
widely tunable numbers of corner states in a SONLS and SOTI, respectively. Our
results break the perception of SONLSs and supply a convenient way to
artificially synthesize exotic topological phases by periodic driving.
The elastic response of mechanical, chemical, and biological systems is often
modeled using a discrete arrangement of Hookean springs, either representing
finite material elements or even the molecular bonds of a system. However, to
date, there is no direct derivation of the relation between a general discrete
spring network and it's corresponding elastic continuum. Furthermore,
understanding the network's mechanical response requires simulations that may
be expensive computationally. Here we report a method to derive the exact
elastic continuum model of any discrete network of springs, requiring network
geometry and topology only. We identify and calculate the so-called
"non-affine" displacements. Explicit comparison of our calculations to
simulations of different crystalline and disordered configurations, shows we
successfully capture the mechanics even of auxetic materials. Our method is
valid for residually stressed systems with non-trivial geometries, is easily
generalizable to other discrete models, and opens the possibility of a rational
design of elastic systems.
Magic-angle twisted bilayer graphene is the best studied physical platform
featuring moire potential induced narrow bands with non-trivial topology and
strong electronic correlations. Despite their significance, the Chern
insulating states observed at a finite magnetic field -- and extrapolating to a
band filling, $s$, at zero field -- remain poorly understood. Unraveling their
nature is among the most important open problems in the province of moir\'e
materials. Here we present the first comprehensive study of interacting
electrons in finite magnetic field while varying the electron density, twist
angle and heterostrain. Within a panoply of correlated Chern phases emerging at
a range of twist angles, we uncover a unified description for the ubiquitous
sequence of states with the Chern number $t$ for $(s,t)=\pm (0,4),
\pm(1,3),\pm(2,2)$ and $\pm(3,1)$. We also find correlated Chern insulators at
unconventional sequences with $s+t\neq \pm 4$, as well as with fractional $s$,
and elucidate their nature.
Excitons -- quasiparticles formed by the binding of an electron and a hole
through electrostatic attraction -- hold promise in the fields of quantum light
confinement and optoelectronic sensing. Atomically thin transition metal
dichalcogenides (TMDs) provide a versatile platform for hosting and
manipulating excitons, given their robust Coulomb interactions and exceptional
sensitivity to dielectric environments. In this study, we introduce a cryogenic
scanning probe photoelectrical sensing platform, termed exciton-resonant
microwave impedance microscopy (ER-MIM). ER-MIM enables ultra-sensitive probing
of exciton polarons and their Rydberg states at the nanoscale. Utilizing this
technique, we explore the interplay between excitons and material properties,
including carrier density, in-plane electric field, and dielectric screening.
Furthermore, we employ deep learning for automated data analysis and
quantitative extraction of electrical information, unveiling the potential of
exciton-assisted nano-electrometry. Our findings establish an invaluable
sensing platform and readout mechanism, advancing our understanding of exciton
excitations and their applications in the quantum realm.
I show how chiral fermions with an exact gauge symmetry in any representation
can appear on the d-dimensional boundary of a finite volume (d + 1)-dimensional
manifold, without any light mirror partners. The condition for it to look like
a local d-dimensional theory is that gauge anomalies cancel, and that the
volume be large. This provides a new paradigm for the lattice regularization of
chiral gauge theories.

Date of feed: Mon, 11 Dec 2023 01:30:00 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) **Phonon topology and winding of spectral weight in graphite. (arXiv:2312.04575v1 [cond-mat.mes-hall])**

N. D. Andriushin, A. S. Sukhanov, A. N. Korshunov, M. S. Pavlovskii, M. C. Rahn, S. E. Nikitin

**Haldane Bundles: A Dataset for Learning to Predict the Chern Number of Line Bundles on the Torus. (arXiv:2312.04600v1 [cond-mat.mes-hall])**

Cody Tipton, Elizabeth Coda, Davis Brown, Alyson Bittner, Jung Lee, Grayson Jorgenson, Tegan Emerson, Henry Kvinge

**A holographic view of topological stabilizer codes. (arXiv:2312.04617v1 [cond-mat.str-el])**

Thomas Schuster, Nathanan Tantivasadakarn, Ashvin Vishwanath, Norman Y. Yao

**Decoherence through Ancilla Anyon Reservoirs. (arXiv:2312.04638v1 [cond-mat.str-el])**

Nayan Myerson-Jain, Taylor L. Hughes, Cenke Xu

**Analytical model and dynamical phase-field simulation of terahertz transmission across ferroelectrics. (arXiv:2312.04824v1 [cond-mat.mes-hall])**

Taorui Chen, Bo Wang, Yujie Zhu, Shihao Zhuang, Long-Qing Chen, Jia-Mian Hu

**Low Resistance Ohmic Contact to P-type Monolayer WSe2. (arXiv:2312.04849v1 [cond-mat.mes-hall])**

Jingxu Xie, Zuocheng Zhang, Haodong Zhang, Vikram Nagarajan, Wenyu Zhao, Haleem Kim, Collin Sanborn, Ruishi Qi, Sudi Chen, Salman Kahn, Kenji Watanabe, Takashi Taniguchi, Alex Zettl, Michael Crommie, James Analytis, Feng Wang

**Enhancement of Goos-H\"{a}nchen shifts in graphene through Fizeau drag effect. (arXiv:2312.04850v1 [cond-mat.mes-hall])**

Rafi Ud Din, Muzamil Shah, Reza Asgari, Gao Xianlong

**Electron Magneto-Hydrodynamics in Graphene. (arXiv:2312.04896v1 [cond-mat.mes-hall])**

Jack N. Engdahl, Aydın Cem Keser, Thomas Schmidt, Oleg P. Sushkov

**Gate-controlled neuromorphic functional transition in an electrochemical graphene transistor. (arXiv:2312.04934v1 [physics.app-ph])**

Chenglin Yu, Shaorui Li, Yongchao Wang, Siyi Zhou, Zhiting Gao, Kaili Jiang, Yayu Wang, Jinsong Zhang

**Beyond spin models in orbitally-degenerate open-shell nanographenes. (arXiv:2312.04938v1 [cond-mat.mes-hall])**

J. C. G. Henriques, D. Jacob, A. Molina-Sánchez, G. Catarina, A. T. Costa, J. Fernández-Rossier

**Dirac plasmon polaritons and magnetic modes in topological-insulator nanoparticles. (arXiv:2312.04958v1 [cond-mat.mes-hall])**

Nikolaos Kyvelos, Vassilios Yannopapas, N. Asger Mortensen, Christos Tserkezis

**Detecting defect dynamics in relativistic field theories far from equilibrium using topological data analysis. (arXiv:2312.04959v1 [hep-ph])**

Viktoria Noel, Daniel Spitz

**Toward Modeling the Structure of Electrolytes at Charged Mineral Interfaces using Classical Density Functional Theory. (arXiv:2312.04976v1 [cond-mat.soft])**

Thomas Petersen

**Quasiparticles-mediated thermal diode effect in Weyl Josephson junctions. (arXiv:2312.05008v1 [cond-mat.supr-con])**

Pritam Chatterjee, Paramita Dutta

**Proximity-induced nonlinear magnetoresistances on topological insulators. (arXiv:2312.05035v1 [cond-mat.mes-hall])**

M. Mehraeen, Steven S.-L. Zhang

**Electron-hole collision-limited resistance of gapped graphene. (arXiv:2312.05066v1 [cond-mat.mes-hall])**

Arseny Gribachov, Vladimir Vyurkov, Dmitry Svintsov

**Scaling of Hybrid QDs-Graphene Photodetectors to Subwavelength Dimension. (arXiv:2312.05083v1 [cond-mat.mtrl-sci])**

Gökhan Kara, Patrik Rohner, Erfu Wu, Dmitry N. Dirin, Roman Furrer, Dimos Poulikakos, Maksym V. Kovalenko, Michel Calame, Ivan Shorubalko

**Manipulating Topological Properties in Bi$_2$Se$_3$/BiSe/TMDC Heterostructures with Interface Charge Transfer. (arXiv:2312.05112v1 [cond-mat.mtrl-sci])**

Xuance Jiang, Turgut Yilmaz, Elio Vescovo, Deyu Lu

**Superconducting Penetration Depth Through a Van Hove Singularity: Sr$_2$RuO$_4$ Under Uniaxial Stress. (arXiv:2312.05130v1 [cond-mat.supr-con])**

Eli Mueller, Yusuke Iguchi, Fabian Jerzembeck, Jorge O. Rodriguez, Marisa Romanelli, Edgar Abarca-Morales, Anastasios Markou, Naoki Kikugawa, Dmitry A. Sokolov, Gwansuk Oh, Clifford W. Hicks, Andrew P. Mackenzie, Yoshiteru Maeno, Vidya Madhavan, Kathryn A. Moler

**Twist driven deep-ultraviolet-wavelength exciton funnel effect in bilayer boron nitride. (arXiv:2312.05135v1 [cond-mat.mtrl-sci])**

Linghan Zhu, Yizhou Wang, Li Yang

**Detecting Atomic Scale Surface Defects in STM of TMDs with Ensemble Deep Learning. (arXiv:2312.05160v1 [cond-mat.mtrl-sci])**

Darian Smalley (1 and 2), Stephanie D. Lough (1 and 2), Luke Holtzman (3), Kaikui Xu (4), Madisen Holbrook (3), Matthew R. Rosenberger (4), J.C. Hone (3), Katayun Barmak (3), Masahiro Ishigami (1 and 2) ((1) Department of Physics, University of Central Florida, (2) NanoScience Technology Center, University of Central Florida, (3) Department of Applied Physics and Applied Mathematics, University of Columbia, (4) Department of Aerospace and Mechanical Engineering, University of Notre Dame)

**Dynamical Signatures of Symmetry Broken and Liquid Phases in an $S=1/2$ Heisenberg Antiferromagnet on the Triangular Lattice. (arXiv:2209.03344v2 [cond-mat.str-el] UPDATED)**

Markus Drescher, Laurens Vanderstraeten, Roderich Moessner, Frank Pollmann

**Revisiting Bloch electrons in magnetic field: Hofstadter physics via hybrid Wannier states. (arXiv:2303.16347v4 [cond-mat.mes-hall] UPDATED)**

Xiaoyu Wang, Oskar Vafek

**Inversion symmetry breaking in the probability density by surface-bulk hybridization in topological insulators. (arXiv:2306.09601v2 [cond-mat.mes-hall] UPDATED)**

Jorge David Castaño-Yepes, Enrique Muñoz

**Nontrivial Aharonov-Bohm effect and alternating dispersion of magnons in cone-state ferromagnetic rings. (arXiv:2308.08486v3 [cond-mat.mes-hall] UPDATED)**

Vera Uzunova, Lukas Körber, Agapi Kavvadia, Gwendolyn Quasebarth, Helmut Schultheiss, Attila Kákay, Boris Ivanov

**Topological analog of the magnetic bit within the Su-Schrieffer-Heeger-Holstein model. (arXiv:2308.11099v2 [cond-mat.mtrl-sci] UPDATED)**

Xinyuan Xu, David Sénéchal, Ion Garate

**Steering-induced phase transition in measurement-only quantum circuits. (arXiv:2309.01315v3 [quant-ph] UPDATED)**

Dongheng Qian, Jing Wang

**Engineering rich two-dimensional higher-order topological phases by flux and periodic driving. (arXiv:2309.01499v4 [cond-mat.mes-hall] UPDATED)**

Ming-Jian Gao, Jun-Hong An

**Predicting the mechanical properties of spring networks. (arXiv:2309.07844v4 [cond-mat.soft] UPDATED)**

Doron Grossman, Arezki Boudaoud

**Theory of correlated Chern insulators in twisted bilayer graphene. (arXiv:2310.15982v2 [cond-mat.mes-hall] UPDATED)**

Xiaoyu Wang, Oskar Vafek

**Harnessing excitons at the nanoscale -- photoelectrical platform for quantitative sensing and imaging. (arXiv:2311.04211v2 [cond-mat.mes-hall] UPDATED)**

Zhurun Ji, Mark E. Barber, Ziyan Zhu, Carlos R. Kometter, Jiachen Yu, Kenji Watanabe, Takashi Taniguchi, Mengkun Liu, Thomas P. Devereaux, Benjamin E. Feldman, Zhixun Shen

**Chiral gauge theory at the boundary between topological phases. (arXiv:2312.01494v2 [hep-lat] UPDATED)**

David B. Kaplan