Found 27 papers in cond-mat Recent years have witnessed a surge of interest in performing measurements
within topological phases of matter, e.g., symmetry-protected topological (SPT)
phases and topological orders. Notably, measurements of certain SPT states have
been known to be related to Kramers-Wannier duality and Jordan-Wigner
transformations, giving rise to long-range entangled states and invertible
phases, such as the Kitaev chain. Moreover, measurements of topologically
ordered states correspond to charge condensations. In this work, we present a
field-theoretic framework for describing measurements within topological field
theories. We employ various lattice models as examples to illustrate the
outcomes of measuring local symmetry operators within topological phases,
demonstrating their agreement with the predictions from field-theoretic
descriptions. We demonstrate that these measurements can lead to SPT,
spontaneous symmetry-breaking, and topologically ordered phases. Specifically,
when there is emergent symmetry after measurement, the remaining symmetry and
emergent symmetry will have a mixed anomaly, which leads to long-ranged
entanglement.
Scanning Tunneling microscopy (STM) is a widely used tool for atomic imaging
of novel materials and its surface energetics. However, the optimization of the
imaging conditions is a tedious process due to the extremely sensitive
tip-surface interaction, and thus limits the throughput efficiency. Here we
deploy a machine learning (ML) based framework to achieve optimal-atomically
resolved imaging conditions in real time. The experimental workflow leverages
Bayesian optimization (BO) method to rapidly improve the image quality, defined
by the peak intensity in the Fourier space. The outcome of the BO prediction is
incorporated into the microscope controls, i.e., the current setpoint and the
tip bias, to dynamically improve the STM scan conditions. We present strategies
to either selectively explore or exploit across the parameter space. As a
result, suitable policies are developed for autonomous convergence of the
control-parameters. The ML-based framework serves as a general workflow
methodology across a wide range of materials.
Moir\'e engineering in two-dimensional van der Waals bilayer crystals has
emerged as a flexible platform for controlling strongly correlated electron
systems. The competition between valleys for the band extremum energy position
in the parent layers is crucial in deciding the qualitative nature of the
moir\'e Hamiltonian since it controls the physics of the moir\'e minibands.
Here we use density functional theory to examine the competition between K and
$\Gamma$ for the valence band maximum in homo- and hetero-bilayers formed from
the transition metal dichalcogenides (TMD), MX\{_2} where M=Mo,W and X=S,Se,Te.
We shed light on how the competition is influenced by interlayer separation,
which can be modified by applying pressure, by external gate-defined electric
fields, and by transition metal atom d-orbital correlations. Our findings are
related to several recent experiments, and contribute to the development of
design rules for moir\'{e} materials.
In this article, we propose a practical way to realize topological surface
Dirac fermions with tunable attractive interaction between them. The approach
involves coating the surface of a topological insulator with a thin film metal
and utilizing the strong-electron phonon coupling in the metal to induce
interaction between the surface fermions. We found that for a given TI and thin
film, the attractive interaction between the surface fermions can be maximally
enhanced when the Dirac point of the TI surface resonates with one of the
quasi-2D quantum-well bands of the thin film. This effect can be considered to
be an example of 'quantum-well resonance'. We also demonstrate that the
superconductivity of the resonating surface fermions can be further enhanced by
choosing a strongly interacting thin film metal or by tuning the spin-orbit
coupling of the TI. This TI-thin film hybrid configuration holds promise for
applications in Majorana-based quantum computations and for the study of
quantum critical physics of strongly attractively interacting surface
topological matter with emergent supersymmetry.
We present a DFT-based investigation of the twist-angle dependent proximity
spin-orbit coupling (SOC) in graphene/TMDC structures. We find that for
Mo-based TMDCs the proximity valley-Zeeman SOC exhibits a maximum at around
15--20{\deg}, and vanishes at 30{\deg}, while for W-based TMDCs we find an
almost linear decrease of proximity valley-Zeeman SOC when twisting from
0{\deg} to 30{\deg}. The induced Rashba SOC is rather insensitive to twisting,
while acquiring a nonzero Rashba phase angle, $\varphi \in [-20;40]${\deg}, for
twist angles different from 0{\deg} and 30{\deg}. This finding contradicts
earlier tight-binding predictions that the Rashba angle can be 90{\deg} in the
studied systems. In addition, we study the influence of several tunability
knobs on the proximity SOC for selected twist angles. By applying a transverse
electric field in the limits of $\pm 2$ V/nm, mainly the Rashba SOC can be
tuned by about 50\%. The interlayer distance provides a giant tunability, since
the proximity SOC can be increased by a factor of 2--3, when reducing the
distance by about 10\%. Encapsulating graphene between two TMDCs, both twist
angles are important to control the interference of the individual proximity
SOCs, allowing to precisely tailor the valley-Zeeman SOC in graphene, while the
Rashba SOC becomes suppressed. Finally, based on our effective Hamiltonians
with fitted parameters, we calculate experimentally measurable quantities such
as spin lifetime anisotropy and charge-to-spin conversion efficiencies. The
spin lifetime anisotropy can become giant, up to $10^4$, in encapsulated
structures. The charge-to-spin conversion, which is due to spin-Hall and
Rashba-Edelstein effects, can lead to twist-tunable non-equilibrium
spin-density polarizations that are perpendicular and parallel to the applied
charge current.
A conventional realization of quantum logic gates and control is based on
resonant Rabi oscillations of the occupation probability of the system. This
approach has certain limitations and complications, like counter-rotating
terms. We study an alternative paradigm for implementing quantum logic gates
based on Landau-Zener-St\"{u}ckelberg-Majorana (LZSM) interferometry with
non-resonant driving and the alternation of adiabatic evolution and
non-adiabatic transitions. Compared to Rabi oscillations, the main differences
are a non-resonant driving frequency and a small number of periods in the
external driving. We explore the dynamics of a multilevel quantum system under
LZSM drives and optimize the parameters for increasing single- and two-qubit
gates speed. We define the parameters of the external driving required for
implementing some specific gates using the adiabatic-impulse model. The LZSM
approach can be applied to a large variety of multi-level quantum systems and
external driving, providing a method for implementing quantum logic gates on
them.
Topological quantum matter exhibits novel transport phenomena driven by
entanglement between internal degrees of freedom, as for instance generated by
spin-orbit coupling effects. Here we report on a direct connection between the
mechanism driving spin relaxation and the intertwined dynamics between spin and
sublattice degrees of freedom in disordered graphene. Beyond having a direct
observable consequence, such intraparticle entanglement is shown to be
resilient to disorder, pointing towards a novel resource for quantum
information processing.
Degeneracies in multilayer graphene, including spin, valley, and layer
degrees of freedom, are susceptible to Coulomb interactions and can result into
rich broken-symmetry states. In this work, we report a ferromagnetic state in
charge neutral ABCA-tetralayer graphene driven by proximity-induced spin-orbit
coupling from adjacent WSe2. The ferromagnetic state is further identified as a
Chern insulator with Chern number of 4, and its Hall resistance reaches 78% and
100% quantization of h/4e2 at zero and 0.4 tesla, respectively. Three
broken-symmetry insulating states, layer-antiferromagnet, Chern insulator and
layer-polarized insulator and their transitions can be continuously tuned by
the vertical displacement field. Remarkably, the magnetic order of the Chern
insulator can be switched by three knobs, including magnetic field, electrical
doping, and vertical displacement field.
We analyze a quantized pumping in a nonlinear non-Hermitian photonic system
with nonadiabatic driving. The photonic system is made of a waveguide array,
where the distances between adjacent waveguides are modulated. It is described
by the Su-Schrieffer-Heeger model together with a saturated nonlinear gain term
and a linear loss term. A topological interface state between the topological
and trivial phases is stabilized by the combination of a saturated nonlinear
gain term and a linear loss term. We study the pumping of the topological
interface state. We define the transfer-speed ratio $\omega /\Omega $ by the
ratio of the pumping speed $% \omega $ of the center of mass of the wave packet
to the driving speed $ \Omega $ of the topological interface. It is quantized
as $\omega /\Omega =1$ in the adiabatic limit. It remains to be quantized for
slow driving even in the nonadiabatic regime, which is a nonadiabatic quantized
pump. On the other hand, there is almost no pump for fast driving. We find a
transition in pumping as a function of the driving speed.
Topological superconductors are a class of unconventional superconducting
materials featuring sub-gap zero-energy Majorana bound modes that hold promise
as a building block for topological quantum computing. In this work, we study
the realization of second-order topology that defines anomalous gapless
boundary modes in a two-orbital superconductor with spin-orbital couplings. We
reveal a time-reversal symmetry-breaking second-order topological
superconducting phase with $d+id$-wave orbital-dependent paring without the
need for the external magnetic field. Remarkably, this orbital-active $d$-wave
paring gives rise to anomalous zero-energy Majorana corner modes, which is in
contrast to conventional chiral $d$-wave pairing, accommodating one-dimensional
Majorana edge modes. Our work not only reveals a unique mechanism of
time-reversal symmetry breaking second-order topological superconductors but
also bridges the gap between second-order topology and orbital-dependent
pairings.
Topological superconductivity emerges in chains or arrays of magnetic atoms
coupled to a superconductor. However, the external controllability of such
systems with gate voltages is detrimental for their future implementation in a
topological quantum computer. Here we showcase the supramolecular assembly of
radical molecules on Pb(111), whose discharge is controlled by the tip of a
scanning tunneling microscope. Charged molecules carry a spin-1/2 state, as
confirmed by observing Yu-Shiba-Rusinov in-gap states by tunneling spectroscopy
at millikelvin temperature. Low energy modes are localized at island boundaries
with a long decay towards the interior, whose spectral signature is consistent
with Majorana zero modes protected by mirror symmetry. Our results open up a
vast playground for the synthesis of gate-tunable organic topological
superconductors.
Generating and tailoring photocurrent in topological materials has immense
importance in fundamental studies and the technological front. Present work
introduces a universal method to generate ultrafast photocurrent in {\it both}
inversion-symmetric and inversion-broken Weyl semimetals with degenerate Weyl
nodes at the Fermi level. Our approach harnesses the asymmetric electronic
population in the conduction band induced by an intense {\it single-color}
circularly polarized laser pulse. It has been found that the induced
photocurrent can be tailored by manipulating helicity and ellipticity of the
employed laser. Moreover, our approach generates photocurrent in realistic
situations when the Weyl nodes are positioned at different energies and have
finite tilt along a certain direction. Present work adds a new dimension on
practical applications of Weyl semimetals for optoelectronics and
photonics-based quantum technologies.
Engineering heterostructures with various types of quantum materials can
provide an intriguing playground for studying exotic physics induced by
proximity effect. Here, we report the successful synthesis of iron-based
superconductor FeSe$_{x}$Te$_{1-x}$ (FST) thin films in the entire composition
of $0 \leq x \leq 1$ and its heterostructure with a magnetic topological
insulator by using molecular beam epitaxy. Superconductivity is observed in the
FST films with an optimal superconducting transition temperature $T_c$ $\sim$
12 K at around x = 0.1. We found that superconductivity survives in the very
Te-rich films ($x \leq 0.05$), showing stark contrast to bulk crystals with
suppression of superconductivity due to an appearance of bicollinear
antiferromagnetism accompanied by monoclinic structural transition. By
examining thickness t dependence on electrical transport properties, we
observed strong suppression of the structural transition in films below t
$\sim$ 100 nm, suggesting that substrate effects may stabilize superconducting
phase near the interface. Furthermore, we fabricated all chalcogenide-based
heterointerface between FST and magnetic topological insulator
(Cr,Bi,Sb)$_{2}$Te$_{3}$ for the first time, observing both superconductivity
and large anomalous Hall conductivity. The anomalous Hall conductivity
increases with decreasing temperature, approaching to the quantized value of
$e^2/h$ down to the measurable minimum temperature at $T_c$. The result
suggests coexistence of magnetic and superconducting gaps at low temperatures
opening at the top and bottom surfaces, respectively. Our novel magnetic
topological insulator/superconductor heterostructure could be an ideal platform
to explore chiral Majorana edge mode.
In this work, we have studied the spin dynamics of a synthethic
Antiferromagnet (SAFM)$|$Heavy Metal (HM)$|$Ferromagnet (FM) double barrier
magnetic tunnel junction (MTJ) in presence of Ruderman-Kittel-Kasuya-Yoside
interaction (RKKYI), interfacial Dzyaloshinskii-Moriya interaction (iDMI),
N\'eel field and Spin-Orbit Coupling (SOC) with different Spin Transfer Torque
(STT). We employ Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation to
investigate the AFM dynamics of the proposed system. We found that the system
exhibits a transition from regular to damped oscillations with the increase in
strength of STT for systems with weaker iDMI than RKKYI while display sustained
oscillatons for system having same order of iDMI and RKKYI. On the other hand
the iDMI dominating system exhibits self-similar but aperiodic patterns in
absence of N\'eel field. In the presence of N\'eel field, the RKKYI dominating
systems exhibit chaotic oscillations for low STT but display sustained
oscillation under moderate STT. Our results suggest that the decay time of
oscillations can be controlled via SOC. The system can works as an oscillator
for low SOC but display nonlinear characteristics with the rise in SOC for
systems having weaker iDMI than RKKYI while an opposite characteristic are
noticed for iDMI dominating systems. We found periodic oscillations under low
external magnetic field in RKKYI dominating systems while moderate field are
necessary for sustained oscillation in iDMI dominating systems. Moreover, the
system exhibits saddle-node bifurcation and chaos under moderate N\'eel field
and SOC with suitable iDMI and RKKYI. In addition, our results indicate that
the magnon lifetime can be enhanced by increasing the strength of iDMI for both
optical and acoustic modes.
Fermionic atoms in optical lattices have served as a compelling model system
to study and emulate the physics of strongly-correlated matter. Driven by the
advances of high-resolution microscopy, the recent focus of research has been
on two-dimensional systems in which several quantum phases, such as
anti-ferromagnetic Mott insulators for repulsive interactions and
charge-density waves for attractive interactions have been observed. However,
the aspired emulations of real materials, such as bilayer graphene, have to
take into account that their lattice structure composes of coupled layers and
therefore is not strictly two-dimensional. In this work, we realize a bilayer
Fermi-Hubbard model using ultracold atoms in an optical lattice and demonstrate
that the interlayer coupling controls a crossover between a planar
anti-ferromagnetically ordered Mott insulator and a band insulator of
spin-singlets along the bonds between the layers. Our work will enable the
exploration of further fascinating properties of coupled-layer Hubbard models,
such as theoretically predicted superconducting pairing mechanisms.
Using first-principle calculations, we investigate the electronic,
topological and superconducting properties of Nb$_3$X (X = Ge, Sn, Sb) and
Ta$_3$Y (Y = As, Sb, Bi) A15 compounds. We demonstrate that these compounds
host Dirac surface states which are related to a nontrivial Z$_2$ topological
value. The spin-orbit coupling (SOC) splits the eightfold degenerate R point
close to the Fermi level enhancing the amplitude of the spin Hall conductance.
Indeed, despite the moderate spin-orbit of the Nb-compounds, a large spin Hall
effect is also obtained in Nb$_3$Ge and Nb$_3$Sn compounds. We show that the
Coulomb interaction opens the gap at the R point thus making more evident the
occurrence of Dirac surface states. We then investigate the superconducting
properties by determining the strength of the electron-phonon BCS coupling. The
evolution of the critical temperature is tracked down to the 2D limit
indicating a reduction of the transition temperature which mainly arises from
the suppression of the density of states at the Fermi level. Finally, we
propose a minimal tight-binding model based on three coupled
Su-Schrieffer-Heeger chains with t$_{2g}$ Ta- and Nb-orbitals reproducing the
spin-orbit splittings at the R point among the $\pi$-bond bands in this class
of compounds. We separate the kinetic parameters in $\pi$ and $\delta$-bonds,
in intradimer and interdimer hoppings and discuss their relevance for the
topological electronic structure. We point out that Nb$_3$Ge might represent a
Z$_2$ topological metal with the highest superconducting temperature ever
recorded.
We investigate anomalous localization phenomena in non-Hermitian systems by
solving a class of generalized Su-Schrieffer-Heeger/Rice-Mele models and by
relating their provenance to fundamental notions of topology, symmetry-breaking
and biorthogonality. We find two flavours of bound states in the continuum,
both stable even in the absence of chiral symmetry. The first being skin bulk
states which are protected by the spectral winding number. The second flavour
is constituted by boundary modes associated with a quantized biorthogonal
polarization. Furthermore, we find the extended state stemming from the
boundary state that delocalizes while remaining in the gap at bulk critical
points. This state may also delocalize within a continuum of localized (skin)
states. These results clarify fundamental aspects of topology, and symmetry in
the light of different approaches to the anomalous non-Hermitan bulk-boundary
correspondence -- and are of direct experimental relevance for mechanical,
electrical and photonic systems.
We propose an exact analytical decimation transformation scheme to explore
the fascinating coexistence of flat bands and Dirac fermions in
three-dimensional coupled kagome systems. Our method allows coarse-graining of
the parameter space that maps the original system to an equivalent low-level
lattice. The decimated system enables defining a quantity in the tight-binding
parameter space that predominantly controls the emergence of a flat band (FB)
and provides a specific criterion for absolute flatness. Likewise, in terms of
atomic separations, we develop a quantity that primarily controls the FB width
in real materials and thus can be helpful in predicting new systems hosting FB
as well as in tuning the FB width. Our predictions on the emergence of the flat
band and Dirac fermions are confirmed for M$_3$X (M= Ni, Mn, Co, Fe; X= Al, Ga,
In, Sn, Cr,...) family of materials, leveraging materials databases and
first-principles calculations. Our work provides an analytical formalism that
enables accurate predictions of FBs in real materials.
Optical absorption in rhombohedral BiFeO$_3$ starts at photon energies below
the photoemission band gap of $\approx$ 3 eV calculated from first principles.
A shoulder at the absorption onset has so far been attributed to low-lying
electronic transitions or to oxygen vacancies. In this work optical spectra are
calculated ab initio to determine the nature of the optical transitions near
the absorption onset of pristine BiFeO$_3$, the effect of electron-hole
interaction, and the spectroscopic signatures of typical defects, i.e. doping
(excess electrons or holes), intrinsic defects (oxygen and bismuth vacancies),
and low-energy structural defects (ferroelectric domain walls).
Modern hybrid superconductor-semiconductor Josephson junction arrays are a
promising platform for analog quantum simulations. Their controllable and
non-sinusoidal energy/phase relation opens the path to implement nontrivial
interactions and study the emergence of exotic quantum phase transitions. Here,
we propose the analysis of an array of hybrid Josephson junctions defining a
two-leg ladder geometry for the quantum simulation of the tricritical Ising
phase transition. This transition provides the paradigmatic example of minimal
conformal models beyond Ising criticality and its excitations are intimately
related with Fibonacci non-Abelian anyons and topological order in two
dimensions. We study this superconducting system and its thermodynamic phases
based on bosonization and matrix-product-states techniques. Its effective
continuous description in terms of a three-frequency sine-Gordon quantum field
theory suggests the presence of the targeted tricritical point and the analysis
of order parameters and correlation lengths confirm this picture. Our results
indicate which experimental observables can be adopted in realistic devices to
probe the physics and the phase transitions of the model. Additionally, our
proposal provides a useful one-dimensional building block to design
two-dimensional scalable Josephson junction arrays with exotic topological
order.
The high kinetic inductance offered by granular aluminum (grAl) has recently
been employed for linear inductors in superconducting high-impedance qubits and
kinetic inductance detectors. Due to its large critical current density
compared to typical Josephson junctions, its resilience to external magnetic
fields, and its low dissipation, grAl may also provide a robust source of
non-linearity for strongly driven quantum circuits, topological
superconductivity, and hybrid systems. Having said that, can the grAl
non-linearity be sufficient to build a qubit? Here we show that a small grAl
volume ($10 \times 200 \times 500 \,\mathrm{nm^3}$) shunted by a thin film
aluminum capacitor results in a microwave oscillator with anharmonicity
$\alpha$ two orders of magnitude larger than its spectral linewidth
$\Gamma_{01}$, effectively forming a transmon qubit. With increasing drive
power, we observe several multi-photon transitions starting from the ground
state, from which we extract $\alpha = 2 \pi \times 4.48\,\mathrm{MHz}$.
Resonance fluorescence measurements of the $|0> \rightarrow |1>$ transition
yield an intrinsic qubit linewidth $\gamma = 2 \pi \times 10\,\mathrm{kHz}$,
corresponding to a lifetime of $16\,\mathrm{\mu s}$. This linewidth remains
below $2 \pi \times 150\,\mathrm{kHz}$ for in-plane magnetic fields up to
$\sim70\,\mathrm{mT}$.
Topological materials have been a main focus of studies in the past decade
due to their protected properties that can be exploited for the fabrication of
new devices. Among them, Weyl semimetals are a class of topological semimetals
with non-trivial linear band crossing close to the Fermi level. The existence
of such crossings requires the breaking of either time-reversal or inversion
symmetry and is responsible for the exotic physical properties. In this work we
identify the full-Heusler compound InMnTi$_2$, as a promising, easy to
synthesize, $T$- and $I$-breaking Weyl semimetal. To correctly capture the
nature of the magnetic state, we employed a novel $\mathrm{DFT}+U$
computational setup where all the Hubbard parameters are evaluated from
first-principles; thus preserving a genuinely predictive \textit{ab initio}
character of the theory. We demonstrate that this material exhibits several
features that are comparatively more intriguing with respect to other known
Weyl semimetals: the distance between two neighboring nodes is large enough to
observe a wide range of linear dispersions in the bands, and only one kind of
such node's pairs is present in the Brillouin zone. We also show the presence
of Fermi arcs stable across a wide range of chemical potentials. Finally, the
lack of contributions from trivial points to the low-energy properties makes
the materials a promising candidate for practical devices.
We study the spectral properties of sparse random graphs with different
topologies and type of interactions, and their implications on the stability of
complex systems, with particular attention to ecosystems. Specifically, we
focus on the behaviour of the leading eigenvalue in different type of random
matrices (including interaction matrices and Jacobian-like matrices), relevant
for the assessment of different types of dynamical stability. By comparing the
results on Erdos-Renyi and Husimi graphs with sign-antisymmetric interactions
or mixed sign patterns, we introduce a sufficient criterion, called strong
local sign stability, for stability not to be affected by system size, as
traditionally implied by the complexity-stability trade-off in conventional
models of random matrices. The criterion requires sign-antisymmetric or
unidirectional interactions and a local structure of the graph such that the
number of cycles of finite length do not increase with the system size. Note
that the last requirement is stronger than the classical local tree-like
condition, which we associate to the less stringent definition of local sign
stability, also defined in the paper. In addition, for strong local sign stable
graphs which show stability to linear perturbations irrespectively of system
size, we observe that the leading eigenvalue can undergo a transition from
being real to acquiring a nonnull imaginary part, which implies a dynamical
transition from nonoscillatory to oscillatory linear response to perturbations.
Lastly, we ascertain the discontinuous nature of this transition.
Two-dimensional second-order topological insulators are characterized by the
presence of topologically protected zero-energy bound states localized at the
corners of a flake. In this paper we theoretically study the occurrence and
features of such corner states inside flakes in the shape of a convex polygon.
We consider two different models, both in Cartan class IIIA, the first obeying
inversion symmetry and the other obeying a combined $\pi/4$ rotation symmetry
and time-reversal symmetry ($\hat{C}_4^z\hat{T}$). By using an analytical
effective model of an edge corresponding to a massive Dirac fermion, we
determine the presence of a corner state between two given edges by studying
the sign of their induced masses and derive general rules for flakes in the
shape of a convex polygon. In particular, we find that the number of corner
states in a flake is always two in the first model, while in the second model
there are either 0, 2 or 4. To corroborate our findings, we focus on flakes of
specific shapes (a triangle and a square) and use a numerical finite-difference
approach to determine the features of the corner states in terms of their
probability density. In the case of a triangular flake, we can change the
position of corner states by rotating the flake in the first model, while in
the second model we can also change their number. Remarkably, when the induced
mass of an edge is zero the corresponding corner state becomes delocalized
along the edge. In the case of a square flake and the model with
$\hat{C}_4^z\hat{T}$ symmetry, there is an orientation of the flake with
respect to the crystal axes, for which the corner states extend along the whole
perimeter of the square.
We build the quasiparticle picture for the tripartite mutual information
(TMI) after quantum quenches in spin chains that can be mapped onto
free-fermion theories. A nonzero TMI (equivalently, topological entropy)
signals quantum correlations between three regions of a quantum many-body
system. The TMI is sensitive to entangled multiplets of more than two
quasiparticles, i.e., beyond the entangled-pair paradigm of the standard
quasiparticle picture. Surprisingly, for some nontrivially entangled multiplets
the TMI is negative at intermediate times. This means that the mutual
information is monogamous, similar to holographic theories. Oppositely, for
multiplets that are "classically" entangled, the TMI is positive. Crucially, a
negative TMI reflects that the entanglement content of the multiplets is not
directly related to the Generalized Gibbs Ensemble (GGE) that describes the
post-quench steady state. Thus, the TMI is the ideal lens to observe the
weakening of the relationship between entanglement and thermodynamics. We
benchmark our results in the XX chain and in the transverse field Ising chain.
In the hydrodynamic limit of long times and large intervals, with their ratio
fixed, exact lattice results are in agreement with the quasiparticle picture.
$GdTe_{3}$ is a layered antiferromagnet belonging to the family of rare-earth
square net tritellurides which has recently attracted much attention due to its
exceptionally high mobility, the presence of a novel unidirectional
incommensurate charge density wave (CDW) state, superconductivity under
pressure, and a cascade of magnetic transitions between 12 and 7 K, whose order
parameters are as yet unknown. Since the itinerant electrons and localized
moments reside on different crystalline planes in this family of compounds,
spin-charge interactions could potentially result in unexpected phases in this
system. In this work, we use spin-polarized scanning tunneling microscopy to
directly image the charge and magnetic orders in $GdTe_{3}$. Below 7 K, we find
a striped antiferromagnetic phase with twice the periodicity of the Gd lattice
and perpendicular to the CDW order. Intriguingly, between 7 and 12 K, we
discover a spin density wave which has the same periodicity as the CDW. Using a
minimal Landau free energy model we show that the spin density wave can arise
from a bulk incipient antiferromagnetic order oriented along the
$\textit{c}$-axis that couples to the CDW order. Our work reveals the order
parameters of the cascade of low temperature magnetic phases in $GdTe_{3}$ and
shows how the interplay between the charge and spin sectors can generate
multiple coexisting magnetic orders in this class of materials.
Motivated by the recent experimental breakthrough on the observation of the
fractional quantum anomalous Hall (FQAH) effects in semiconductor and graphene
moir\'{e} materials, we explore the rich physics associated with the
coexistence of FQAH effect and the charge density wave (CDW) order that
spontaneously breaks the translation symmetry. We refer to a state with both
properties as "FQAH-crystal". We show that the interplay between FQAH effect
and CDW can lead to a rich phase diagram including multiple topological phases
and topological quantum phase transitions at the same moir\'e filling. In
particular, we demonstrate the possibility of direct quantum phase transitions
from a FQAH-crystal with Hall conductivity $\sigma_H = - 2/3$ to a trivial CDW
insulator with $\sigma_H = 0$, and more interestingly, to a QAH-crystal with
$\sigma_H= -1$.

Date of feed: Mon, 30 Oct 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) **Measuring Topological Field Theories: Lattice Models and Field-Theoretic Description. (arXiv:2310.17740v1 [cond-mat.str-el])**

Yabo Li, Mikhail Litvinov, Tzu-Chieh Wei

**Autonomous convergence of STM control parameters using Bayesian Optimization. (arXiv:2310.17765v1 [physics.app-ph])**

Ganesh Narasimha, Saban Hus, Arpan Biswas, Rama Vasudevan, Maxim Ziatdinov

**Ab-initio study of the energy competition between \Gamma and K valleys in bilayer transition metal dichalcogenides. (arXiv:2310.17824v1 [cond-mat.mtrl-sci])**

Sam Olin, Erekle Jmukhadze, Allan H. MacDonald, Wei-Cheng Lee

**Realizing attractive interacting topological surface fermions: A resonating TI- thin film hybrid platform. (arXiv:2310.17847v1 [cond-mat.supr-con])**

Saran Vijayan, Fei Zhou

**Twist- and gate-tunable proximity spin-orbit coupling, spin relaxation anisotropy, and charge-to-spin conversion in heterostructures of graphene and transition-metal dichalcogenides. (arXiv:2310.17907v1 [cond-mat.mes-hall])**

Klaus Zollner, Simão M. João, Branislav K. Nikolić, Jaroslav Fabian

**Alternative fast quantum logic gates using nonadiabatic Landau-Zener-St\"{u}ckelberg-Majorana transitions. (arXiv:2310.17932v1 [quant-ph])**

A. I. Ryzhov, O. V. Ivakhnenko, S. N. Shevchenko, M. F. Gonzalez-Zalba, Franco Nori

**Resilient Intraparticle Entanglement and its Manifestation in Spin Dynamics of Disordered Dirac Matter. (arXiv:2310.17950v1 [cond-mat.mes-hall])**

Jorge Martinez Romeral, Aron W. Cummings, Stephan Roche

**Observation of Chern insulator in crystalline ABCA-tetralayer graphene with spin-orbit coupling. (arXiv:2310.17971v1 [cond-mat.mes-hall])**

Yating Sha, Jian Zheng, Kai Liu, Hong Du, Kenji Watanabe, Takashi Taniguchi, Jinfeng Jia, Zhiwen Shi, Ruidan Zhong, Guorui Chen

**Nonadiabatic nonlinear non-Hermitian quantized pumping. (arXiv:2310.17987v1 [cond-mat.mes-hall])**

Motohiko Ezawa, Natsuko Ishida, Yasutomo Ota, Satoshi Iwamoto

**Theory of $d + id$ Second-Order Topological Superconductors. (arXiv:2310.17992v1 [cond-mat.supr-con])**

Zi-Ming Wang, Meng Zeng, Chen Lu, Da-Shuai Ma, Rui-Xing Zhang, Lun-Hui Hu, Dong-Hui Xu

**Gate-tunable topological superconductivity in a supramolecular electron spin lattice. (arXiv:2310.18134v1 [cond-mat.supr-con])**

Jung-Ching Liu, Chao Li, Richard Hess, Hongyan Chen, Carl Drechsel, Ping Zhou, Robert Häner, Ulrich Aschauer, Thilo Glatzel, Silvio Decurtins, Daniel Loss, Jelena Klinovaja, Shi-Xia Liu, Wulf Wulfhekel, Ernst Meyer, Rémy Pawlak

**Tailoring Photocurrent in Weyl Semimetals via Intense Laser Irradiation. (arXiv:2310.18145v1 [physics.optics])**

Amar Bharti, Gopal Dixit

**Molecular beam epitaxy of superconducting FeSe$_{x}$Te$_{1-x}$ thin films interfaced with magnetic topological insulators. (arXiv:2310.18147v1 [cond-mat.supr-con])**

Yuki Sato, Soma Nagahama, Ilya Belopolski, Ryutaro Yoshimi, Minoru Kawamura, Atsushi Tsukazaki, Naoya Kanazawa, Kei S. Takahashi, Masashi Kawasaki, Yoshinori Tokura

**Effect of interfacial Dzyaloshinskii-Moriya interaction in spin dynamics of an Antiferromagnet coupled Ferromagnetic double-barrier Magnetic Tunnel Junction. (arXiv:2310.18175v1 [cond-mat.supr-con])**

Reeta Devi, Nimisha Dutta, Arindam Boruah, Saumen Acharjee

**Competing magnetic orders in a bilayer Hubbard model with ultracold atoms. (arXiv:2310.18204v1 [cond-mat.quant-gas])**

Marcell Gall, Nicola Wurz, Jens Samland, Chun Fai Chan, Michael Köhl

**Superconducting Nb$_3$Sn and related A15 compounds are Z$_2$ topological metals with three coupled Su-Schrieffer-Heeger chains. (arXiv:2310.18245v1 [cond-mat.supr-con])**

Raghottam M. Sattigeri, Giuseppe Cuono, Ghulam Hussain, Xing Ming, Angelo Di Bernardo, Carmine Attanasio, Mario Cuoco, Carmine Autieri

**Non-Hermitian extended midgap states and bound states in the continuum. (arXiv:2310.18270v1 [physics.optics])**

Maria Zelenayova, Emil J. Bergholtz

**Origin of flat bands and non-trivial topology in coupled kagome lattices. (arXiv:2310.18276v1 [cond-mat.mtrl-sci])**

Anumita Bose, Arka Bandyopadhyay, Awadhesh Narayan

**Optical signatures of defects in BiFeO$_3$. (arXiv:2310.18296v1 [cond-mat.mtrl-sci])**

Sabine Körbel

**Quantum simulation of the tricritical Ising model in tunable Josephson junction ladders. (arXiv:2310.18300v1 [cond-mat.mes-hall])**

Lorenzo Maffi, Niklas Tausendpfund, Matteo Rizzi, Michele Burrello

**Implementation of a transmon qubit using superconducting granular aluminum. (arXiv:1911.02333v3 [quant-ph] UPDATED)**

Patrick Winkel, Kiril Borisov, Lukas Grünhaupt, Dennis Rieger, Martin Spiecker, Francesco Valenti, Alexey V. Ustinov, Wolfgang Wernsdorfer, Ioan M. Pop

**The type-I antiferromagnetic Weyl semimetal InMnTi$_2$. (arXiv:2208.11412v3 [cond-mat.mtrl-sci] UPDATED)**

Davide Grassano, Luca Binci, Nicola Marzari

**Local sign stability and its implications for spectra of sparse random graphs and stability of ecosystems. (arXiv:2303.09897v2 [cond-mat.dis-nn] UPDATED)**

Pietro Valigi, Izaak Neri, Chiara Cammarota

**Corner states of two-dimensional second-order topological insulators with a chiral symmetry and broken time reversal and charge conjugation. (arXiv:2304.06854v2 [cond-mat.mes-hall] UPDATED)**

Joseph Poata, Fabio Taddei, Michele Governale

**Negative tripartite mutual information after quantum quenches in integrable systems. (arXiv:2305.10245v2 [cond-mat.stat-mech] UPDATED)**

Fabio Caceffo, Vincenzo Alba

**Atomic-Scale Visualization of a Cascade of Magnetic Orders in the Layered Antiferromagnet $GdTe_{3}$. (arXiv:2308.15691v2 [cond-mat.str-el] UPDATED)**

Arjun Raghavan, Marisa Romanelli, Julian May-Mann, Anuva Aishwarya, Leena Aggarwal, Anisha G. Singh, Maja D. Bachmann, Leslie M. Schoop, Eduardo Fradkin, Ian R. Fisher, Vidya Madhavan

**Intertwined fractional quantum anomalous Hall states and charge density waves. (arXiv:2310.11632v2 [cond-mat.str-el] UPDATED)**

Xue-Yang Song, Chao-Ming Jian, Liang Fu, Cenke Xu