Found 35 papers in cond-mat
Date of feed: Fri, 12 Jan 2024 01:30:00 GMT

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First-principles calculations of the electronic and optical properties of penta-graphene monolayer: study of many-body effects. (arXiv:2401.05429v1 [physics.comp-ph])
Babak Minaie, Seyed A. Ketabi, José M. De Sousa

In the present work, first-principles calculations based on the density functional theory (DFT), GW approximation and Bethe-Salpeter equation (BSE) are performed to study the electronic and optical properties of penta-graphene (PG) monolayer. The results indicated that PG is a semiconductor with an indirect band gap of approximately 2.32 eV at the DFT- GGA level. We found that the utilization of the GW approximation based on many-body perturbation theory led to an increase in the band gap, resulting in a quasi-direct gap of 5.35 eV. Additionally, we employed the G0W0 - RP A and G0W0 - BSE approximations to calculate the optical spectra in the absence and in the presence of electron-hole interaction, respectively. The results demonstrated that the inclusion of electron-hole interaction caused a red-shift of the absorption spectrum towards lower energies compared to the spectrum obtained from the G0W0 - RP A approximation. With the electron-hole interaction, it is found that the optical absorption spectra are dominated by the first bound exciton with a significant binding energy 3.07 eV. The study concluded that the PG monolayer, with a wider band gap and enhanced excitonic effects, holds promise as a suitable candidate for the design and fabrication of optoelectronic components.

On the zero-field quantization of the anomalous quantum Hall effect in moir\'e 2D layers. (arXiv:2401.05485v1 [cond-mat.mes-hall])
Sankar Das Sarma, Ming Xie

In recent breakthrough experiments, twisted moir\'e layers of transition metal dichalcogenides are found to manifest both integer (IQAHE) and fractional (FQAHE) quantum anomalous Hall effects in zero applied magnetic field because of the underlying flat band topology and spontaneous breaking of the time reversal invariance. In the current work, we critically analyze the experimental values of the quantized conductance in each case to emphasize the role of disorder in the problem, pointing out that obtaining accurate quantized conductance in future experiments would necessitate better contacts and lower disorder.

Topological superconductivity induced by a Kitaev spin liquid. (arXiv:2401.05488v1 [cond-mat.supr-con])
Sondre Duna Lundemo, Asle Sudbø

We study the effective low-energy fermionic theory of the Kondo-Kitaev model to leading order in the Kondo coupling. Our main goal is to understand the nature of the superconducting instability induced in the proximate metal due to its coupling to spin fluctuations of the spin liquid. The special combination of the low-energy modes of a graphene-like metal and the form of the interaction induced by the Majorana excitations of the spin liquid furnish chiral superconducting order with $p_x + \mathrm{i} p_y$ symmetry. Computing its response to a $\mathrm{U}(1)$ gauge field moreover shows that this superconducting state is topologically non-trivial, characterized by a first Chern number of $\pm 2$.

A Cold-Atom Particle Collider. (arXiv:2401.05489v1 [cond-mat.quant-gas])
Guo-Xian Su, Jesse Osborne, Jad C. Halimeh

A major objective of the strong ongoing drive to realize quantum simulators of gauge theories is achieving the capability to probe collider-relevant physics on them. In this regard, a highly pertinent and sought-after application is the controlled collisions of elementary and composite particles, as well as the scattering processes in their wake. Here, we propose particle-collision experiments in a cold-atom quantum simulator for a $1+1$D $\mathrm{U}(1)$ lattice gauge theory with a tunable topological $\theta$-term, where we demonstrate an experimentally feasible protocol to impart momenta to elementary (anti)particles and their meson composites. We numerically benchmark the collisions of moving wave packets for both elementary and composite particles, uncovering a plethora of rich phenomena, such as oscillatory string dynamics in the wake of elementary (anti)particle collisions due to confinement. We also probe string inversion and entropy production processes across Coleman's phase transition through far-from-equilibrium quenches. We further demonstrate how collisions of composite particles unveil their internal structure. Our work paves the way towards the experimental investigation of collision dynamics in state-of-the-art quantum simulators of gauge theories, and sets the stage for microscopic understanding of collider-relevant physics in these platforms.

Non-Gaussian diffusive fluctuations in Dirac fluids. (arXiv:2401.05494v1 [cond-mat.stat-mech])
Sarang Gopalakrishnan, Ewan McCulloch, Romain Vasseur

Dirac fluids - interacting systems obeying particle-hole symmetry and Lorentz invariance - are among the simplest hydrodynamic systems; they have also been studied as effective descriptions of transport in strongly interacting Dirac semimetals. Direct experimental signatures of the Dirac fluid are elusive, as its charge transport is diffusive as in conventional metals. In this paper we point out a striking consequence of fluctuating relativistic hydrodynamics: the full counting statistics (FCS) of charge transport is highly non-gaussian. We predict the exact asymptotic form of the FCS, which generalizes a result previously derived for certain interacting integrable systems. A consequence is that, starting from quasi-one dimensional nonequilibrium initial conditions, charge noise in the hydrodynamic regime is parametrically enhanced relative to that in conventional diffusive metals.

Static and fluctuating zigzag order, and possible signatures of Kitaev physics, in torque measurements of ${\alpha}$-RuCl${_3}$. (arXiv:2401.05546v1 [cond-mat.str-el])
Shaun Froude-Powers, Subin Kim, Jacob Gordon, Hae-Young Kee, Young-June Kim, Stephen R. Julian

We have measured magnetic torque on a T${_N}$ = 7 K single crystal of ${\alpha}$-RuCl${_3}$ , as a function of the field angle in the ab-plane, focusing on temperatures between 2 and 20 K and fields from 0 to 9 T. We find a rich spectrum of signals, many of which can be classified by their angular periodicity. The sample shows an oscillation with a period of 180$^{\circ}$ (i.e. two-fold periodicity) which we argue is due to residual strain within the crystal, rather than being intrinsic. In addition, within the magnetically ordered zigzag phase there is a 60$^{\circ}$ period (i.e. six-fold) sawtooth pattern, which can be explained by reorientation of the zigzag domains as the crystal rotates in the applied field. Suppressing the zigzag order with an applied field above ${\sim}$ 8 T at low temperature, a six-fold sinusoidal signal remains, suggesting that there is fluctuating zigzag order in the putative field-induced quantum spin liquid state. Finally, our key finding is a sharp, step-like feature that appears at low temperature for fields just above the zigzag phase boundary, at the so-called B2-axes. This is similar to theoretically predicted behaviour for a state with Ising topological order, which is expected for a Kitaev spin liquid in an applied magnetic field.

Topological defects in multi-layered swarming bacteria. (arXiv:2401.05560v1 [cond-mat.soft])
Victor Yashunsky, Daniel J.G. Pearce, Gil Ariel, Avraham Be'er

Topological defects, which are singular points in a director field, play a major role in shaping active systems. Here, we experimentally study topological defects and the flow patterns around them, that are formed during the highly rapid dynamics of swarming bacteria. The results are compared to the predictions of two-dimensional active nematics. We show that, even though some of the assumptions underlying the theory do not hold, the swarm dynamics is in agreement with two-dimensional nematic theory. In particular, we look into the multi-layered structure of the swarm, which is an important feature of real, natural colonies, and find a strong coupling between layers. Our results suggest that the defect-charge density is hyperuniform, i.e., that long range density-fluctuations are suppressed.

A Universal Scaling Law for Intrinsic Fracture Energy of Networks. (arXiv:2401.05564v1 [cond-mat.mtrl-sci])
Chase Hartquist, Shu Wang, Qiaodong Cui, Wojciech Matusik, Bolei Deng, Xuanhe Zhao

Networks of interconnected materials permeate throughout nature, biology, and technology due to exceptional mechanical performance. Despite the importance of failure resistance in network design and utility, no existing physical model effectively links strand mechanics and connectivity to predict bulk fracture. Here, we reveal a universal scaling law that bridges these levels to predict the intrinsic fracture energy of diverse networks. Simulations and experiments demonstrate its remarkable applicability to a breadth of strand constitutive behaviors, topologies, dimensionalities, and length scales. We show that local strand rupture and nonlocal energy release contribute synergistically to the measured intrinsic fracture energy in networks. These effects coordinate such that the intrinsic fracture energy scales independent of the energy to rupture a strand; it instead depends on the strand rupture force, breaking length, and connectivity. Our scaling law establishes a physical basis for understanding network fracture and a framework for fabricating tough materials from networks across multiple length scales.

A lattice regularization of Weyl fermions in a gravitational background. (arXiv:2401.05636v1 [hep-lat])
Shoto Aoki, Hidenori Fukaya, Naoto Kan

We report on a lattice fermion formulation with a curved domain-wall mass term to nonperturbatively describe fermions in a gravitational background. In our previous work in 2022, we showed under the time-reversal symmetry that the edge-localized massless Dirac fermion appears on one and two-dimensional spherical domain-walls and the spin connection is induced on the lattice in a consistent way with continuum theory. In this work, we extend our study to the Shamir type curved domain-wall fermions without the time-reversal symmetry. We find in the free fermion case that a single Weyl fermion appears on the edge, and feels gravity through the induced spin connection. With a topologically nontrivial $U(1)$ gauge potential, however, we find an oppositely chiral zero mode at the center where the gauge field is singular.

Josephson Junction of Nodal Superconductors with Rashba and Ising Spin-Orbit coupling. (arXiv:2401.05685v1 [cond-mat.mes-hall])
Gal Cohen, Ranjani Seshadri, Maxim Khodas, Dganit Meidan

We study the effect of a Rashba spin-orbit coupling on the nodal superconducting phase of an Ising superconductor. Such nodal phase was predicted to occur when applying an in-plane field beyond the Pauli limit to a superconducting monolayer transition metal dichalcogenides (TMD). Generically, Rashba spin-orbit is known to lift the chiral symmetry that protects the nodal points, resulting in a fully gapped phase. However, when the magnetic field is applied along the $\Gamma -K $ line, a residual vertical mirror symmetry protects a nodal crystalline phase. We study a single-band tight-binding model that captures the low energy physics around the $\Gamma $ pocket of monolayer TMD. We calculate the topological properties, the edge state structure, and the current phase relation in a Josephson junction geometry of the nodal crystalline phase. We show that while the nodal crystalline phase is characterized by localized edge modes on non-self-reflecting boundaries, the current phase relation exhibits a trivial $2\pi $ periodicity in the presence of Rashba spin-orbit coupling.

Atomic Scale Quantum Anomalous Hall Effect in Monolayer Graphene/$\rm MnBi_{2}Te_{4}$ Heterostructure. (arXiv:2401.05691v1 [cond-mat.mes-hall])
Yueh-Ting Yao, Suyang Xu, Tay-Rong Chang

The two-dimensional quantum anomalous Hall (QAH) effect is direct evidence of non-trivial Berry curvature topology in condensed matter physics. Searching for QAH in 2D materials, particularly with simplified fabrication methods, poses a significant challenge in future applications. Despite numerous theoretical works proposed for the QAH effect with $C=2$ in graphene, neglecting magnetism sources such as proper substrate effects remain experimental evidence absent. In this work, we propose the QAH effect in graphene/$\rm MnBi_{2}Te_{4}$ (MBT) heterostructure based on density-functional theory (DFT). The monolayer MBT introduces spin-orbital coupling, Zeeman exchange field, and Kekul$\rm \acute{e}$ distortion as a substrate effect into graphene, resulting in QAH with $C=1$ in the heterostructure. Our effective Hamiltonian further presents a rich phase diagram that has not been studied previously. Our work provides a new and practical way to explore the QAH effect in monolayer graphene and the magnetic topological phases by the flexibility of MBT family materials.

Dynamical Chiral Symmetry and Symmetry-Class Conversion in Floquet Topological Insulators. (arXiv:2401.05697v1 [cond-mat.mes-hall])
Mohamed Assili, Panagiotis Kotetes

In this work, we discuss properties with no static counterpart arising in Floquet topological insulators with a dynamical chiral symmetry (DCS), i.e., a chiral symmetry which is present while driving. We explore the topological properties of Floquet insulators possessing a DCS which either does or does not survive upon taking the static limit. We consider the case of harmonic drives and employ a general framework using the quasi-energy operator in frequency space. We find that for a DCS with no static analog, the presence of driving has a negligible impact on the topological phases associated with zero quasi-energy. In stark contrast, topological gaps can open at $\pi$ quasi-energy and mainly occur at momenta where the driving perturbation vanishes. We confirm the above general predictions for an extended Kitaev chain model in the BDI symmetry class. Another possibility that opens up when adding the drive, while preserving chiral symmetry, is symmetry-class conversion. We demonstrate such an effect for a static CI class Hamiltonian which is topologically trivial in 1D. By considering a suitable driving, we obtain a CI$\rightarrow$AIII transition, which now enables the system to harbor topological $\pi$-modes. Notably, the arising topological phases strongly depend on whether the DCS has a static analog or not. Our results bring Floquet insulators with nonstandard DCS forward as ideal candidate platforms for engineering and manipulating topological $\pi$-modes.

Skyrmions with a high topological number and phase transition in two-dimensional frustrated J1-J2 magnets. (arXiv:2401.05719v1 [physics.comp-ph])
Hongliang Hu, Zhong Shen, Zheng Chen, Xiaoping Wu, Tingting Zhong, Changsheng Song

With the rapidly expanded field of two-dimensional(2D) magnetic materials, the frustrated magnetic skyrmions are attracting growing interest recently. Here, based on hexagonal close-packed (HCP) lattice of $J_1$-$J_2$ Heisenberg spins model, we systematically investigate the frustrated skyrmions and phase transition by micromagnetic simulations and first-principles calculations. The results show that four spin phases of antiferromagnetic, labyrinth domain, skyrmion and ferromagnetic textures are determined by the identified ranges of $J_1$-$J_2$. Importantly, skyrmion phase with an increasing topological number ($Q$) covers a wider $J_1$-$J_2$ area. Then, the diameter of skyrmions can be tuned by the frustration strength ($|J_2/J_1|$) or external magnetic field. Besides, a phase transition from N$\acute{e}$el to Bloch type skyrmion is observed due to the change of the helicity with the variation of $|J_2/J_1|$. Furthermore, as increasing magnetic field, the skyrmions with high $Q$ ($\ge 3$) tend to split into the ones with $Q=1$, thereby achieving a lower systematic energy. Additionally, we find that the CoCl$_2$ monolayer satisfies the requirement of the frustrated $J_1$-$J_2$ magnet, and the related magnetic behaviors agree with the above conclusions. The frustration-induced skyrmions are stable without the manipulation of temperature and magnetic field. Our results may open a possible way toward spintronic applications based on High-topological-number and nanoscale topological spin textures of skyrmions.

Micromagnetic simulations of the size dependence of the Curie temperature in ferromagnetic nanowires and nanolayers. (arXiv:2401.05722v1 [cond-mat.mes-hall])
Clémentine Courtès, Matthieu Boileau, Raphaël Côte, Paul-Antoine Hervieux, Giovanni Manfredi

We solve the Landau-Lifshitz-Gilbert equation in the finite-temperature regime, where thermal fluctuations are modeled by a random magnetic field whose variance is proportional to the temperature. By rescaling the temperature proportionally to the computational cell size $\Delta x$ ($T \to T\,\Delta x/a_{\text{eff}}$, where $a_{\text{eff}}$ is the lattice constant) [M. B. Hahn, J. Phys. Comm., 3:075009, 2019], we obtain Curie temperatures $T_{\text{C}}$ that are in line with the experimental values for cobalt, iron and nickel. For finite-sized objects such as nanowires (1D) and nanolayers (2D), the Curie temperature varies with the smallest size $d$ of the system. We show that the difference between the computed finite-size $T_{\text{C}}$ and the bulk $T_{\text{C}}$ follows a power-law of the type: $(\xi_0/d)^\lambda$, where $\xi_0$ is the correlation length at zero temperature, and $\lambda$ is a critical exponent. We obtain values of $\xi_0$ in the nanometer range, also in accordance with other simulations and experiments. The computed critical exponent is close to $\lambda=2$ for all considered materials and geometries. This is the expected result for a mean-field approach, but slightly larger than the values observed experimentally.

Giant piezoelectric effects of topological structures in stretched ferroelectric membranes. (arXiv:2401.05789v1 [cond-mat.mtrl-sci])
Yihao Hu, Jiyuan Yang, Shi Liu

Freestanding ferroelectric oxide membranes emerge as a promising platform for exploring the interplay between topological polar ordering and dipolar interactions that are continuously tunable by strain. Our investigations combining density functional theory (DFT) and deep-learning-assisted molecular dynamics simulations demonstrate that DFT-predicted strain-driven morphotropic phase boundary involving monoclinic phases manifest as diverse domain structures at room temperatures, featuring continuous distributions of dipole orientations and mobile domain walls. Detailed analysis of dynamic structures reveals that the enhanced piezoelectric response observed in stretched PbTiO$_3$ membranes results from small-angle rotations of dipoles at domain walls, distinct from conventional polarization rotation mechanism and adaptive phase theory inferred from static structures. We identify a ferroelectric topological structure, termed "dipole spiral," which exhibits a giant intrinsic piezoelectric response ($>$320 pC/N). This helical structure, primarily stabilized by entropy and possessing a rotational zero-energy mode, unlocks new possibilities for exploring chiral phonon dynamics and dipolar Dzyaloshinskii-Moriya-like interactions.

A Microscopic study of Magnetic monopoles in Topological Insulators. (arXiv:2401.05804v1 [hep-lat])
Shoto Aoki, Hidenori Fukaya, Naoto Kan, Mikito Koshino, Yoshiyuki Matsuki

In this article, we analyze a magnetic monopole in topological insulators. The monopole obtain a fractional electric charge because of the Witten effect. We consider this system with a microscopic view by adding the Wilson term to the ordinary Dirac Hamiltonian. The Wilson term yields the positive mass shift to the effective mass of the electrons, then the curved domain-wall is dynamically generated around the monopole. The zero-modes of the electrons are localized on the domain-wall, which can be identified as the source of the electric charge.

Ions and dipoles in electric field: Nonlinear polarization and field-dependent chemical reaction. (arXiv:2401.05825v1 [cond-mat.soft])
Akira Onuki

We investigate electric-field effects in dilute electrolytes with nonlinear polarization. As a first example of such systems, we add a dipolar component with a relatively large dipole moment $\mu_0$ to an aqueous electrolyte. As a second example, the solvent itself exhibits nonlinear polarization near charged objects. For such systems, we present a Ginzburg-Landau free energy and introduce field-dependent chemical potentials, entropy density, and stress tensor, which satisfy general thermodynamic relations. In the first example, the dipoles accumulate in high-field regions, as predicted by Abrashikin {\it et al}.$[$Phys.Rev.Lett. {\bf 99}, 077801 (2007)$]$. Finally, we consider the case, where Bjerrum ion pairs form a dipolar component with nonlinear polarization. The Bjerrum dipoles accumulate in high-field regions, while field-induced dissociation was predicted by Onsager $[$J. Chem. Phys.{\bf 2}, 599 (1934)$]$. We present an expression for the field-dependent association constant $K(E)$, which depends on the field strength nonmonotonically.

Ferroelectric topological superconductor. (arXiv:2401.05847v1 [cond-mat.supr-con])
Xiaoming Zhang, Pei Zhao, Feng Liu

Two-dimensional topological superconductor (TSC) represents an exotic quantum material with quasiparticle excitation manifesting in dispersive Majorana mode (DMM) at the boundaries. A domain-wall DMM can arise at the boundary between two TSC domains with opposite Chern numbers or with a $\pi$-phase shift in their pairing gap, which can only be tuned by magnetic field. Here we propose the concept of ferroelectric (FE) TSC, which not only enriches the domain-wall DMMs but also significantly makes them electrically tunable. The $\pi$-phase shift of the pairing gap is shown to be attained between two TSC domains of opposite FE polarization, and switchable by reversing FE polarizations. In combination with ferromagnetic (FM) polarization, the domain wall can host helical, doubled chiral, and fused DMMs, which can be transferred into each other by changing the direction of electrical and/or magnetic field. Furthermore, based on first-principles calculations, we demonstrate $\alpha$-In$_2$Se$_3$ to be a promising FE TSC candidate in proximity with a FM layer and a superconductor substrate. We envision that FE TSC will significantly ease the manipulation of DMM by electrical field to realize fault-tolerant quantum computation.

Optical and acoustic plasmons in the layered material Sr$_2$RuO$_4$. (arXiv:2401.05880v1 [cond-mat.str-el])
J. Schultz, A. Lubk, F. Jerzembeck, N. Kikugawa, M. Knupfer, D. Wolf, B. Büchner, J. Fink

We use momentum-dependent electron energy-loss spectroscopy in transmission to study collective charge excitations in the "strange" layer metal Sr$_2$RuO$_4$. We cover a complete range between in-plane and out-of-plane oscillations. Outside of the classical range of electron-hole excitations, leading to a Landau damping, we observe well defined plasmons. The optical (acoustic) plasmon due to an in-phase (out-of-phase) charge oscillation of neighbouring layers exhibits a quadratic (linear) dispersion. Using a model for the Coulomb interaction of the charges in a layered system, it is possible to describe the complete range of plasmon excitations in a mean-field random phase approximation without taking correlation effects into account. There are no signs of over-damped plasmons predicted by holographic theories. This indicates that long wavelength charge excitations are not influenced by local correlation effects such as on-site Coulomb interaction and Hund's exchange interaction.

Intercalation-induced states at the Fermi level and the coupling of intercalated magnetic ions to conducting layers in Ni$_{1/3}$NbS$_2$. (arXiv:2401.05884v1 [cond-mat.mtrl-sci])
Yuki Utsumi Boucher, Izabela Biało, Mateusz A. Gala, Wojciech Tabiś, Marcin Rosmus, Natalia Olszowska, Jacek J. Kolodziej, Bruno Gudac, Mario Novak, Naveen Kumar Chogondahalli Muniraju, Ivo Batistić, Neven Barišić, Petar Popčević, Eduard Tutiš

The magnetic sublayers introduced by intercalation into the host transition-metal dichalcogenide (TMD) are known to produce various magnetic states. The magnetic sublayers and their magnetic ordering strongly modify the electronic coupling between layers of the host compound. Understanding the roots of this variability is a significant challenge. Here we employ the angle-resolved photoelectron spectroscopy at various photon energies, the {\it ab initio} electronic structure calculations, and modeling to address the particular case of Ni-intercalate, Ni$_{1/3}$NbS$_2$. We find that the bands around the Fermi level bear the signature of a strong yet unusual hybridization between NbS$_2$ conduction band states and the Ni 3$d$ orbitals. The hybridization between metallic NbS$_2$ layers is almost entirely suppressed in the central part of the Brillouin zone, including the part of the Fermi surface around the $\mathrm{\Gamma}$ point. Simultaneously, it gets very pronounced towards the zone edges. It is shown that this behavior is the consequence of the rather exceptional, {\it symmetry imposed}, spatially strongly varying, {\it zero total} hybridization between relevant Ni magnetic orbitals and the neighboring Nb orbitals that constitute the metallic bands. We also report the presence of the so-called $\beta$-feature, discovered only recently in two other magnetic intercalates with very different magnetic orderings. In Ni$_{1/3}$NbS$_2$, the feature shows only at particular photon energies, indicating its bulk origin. Common to prior observations, it appears as a series of very shallow electron pockets at the Fermi level, positioned along the edge of the Brillouin zone. Unforeseen by {\it ab initio} electronic calculations, and its origin still unresolved, the feature appears to be a robust consequence of the intercalation of 2H-NbS$_2$ with magnetic ions.

Cu$_2$ZnSiTe$_4$: A potential thermoelectric material with promising electronic transport. (arXiv:2401.05903v1 [cond-mat.mtrl-sci])
Himanshu Sharma, Bhawna Sahni, Tanusri Saha-Dasgupta, Aftab Alam

Transition metal-based quaternary chalcogenides have gathered immense attention for various renewable energy applications including thermoelectrics (TE). While low-symmetry and complex structure help to achieve low thermal conductivity, the TE power factor and hence the figure of merit (ZT) remains low which hinders to promote these class of materials for future TE applications. Here, we investigated the TE properties of a new system, Cu$_2$ZnSiTe$_4$, with improved electronic transport using first-principles calculation. The presence of heavy chalcogen like Te, helps to achieve a relatively low bandgap (0.58 eV). This, together with unique electronic band topology, leads to a promising value of power-factor of 3.95(n-type) and 3.06(p-type) mWm$^{-1}$K$^{-2}$ at 900 K. Te atoms also play a crucial role in mixing the optical and acoustic phonon branches which, in turn, are responsible for reduced lattice thermal conductivity ($\sim$0.7 Wm$^{-1}$K$^{-1}$ at high temperature). Though the thermal conductivity is not appreciably low, the electronic transport properties (power factor) are quite favorable to yield promising TE figure of merit (ZT $\sim$2.67 (n-type) and $\sim$2.11 (p-type) at 900 K). We propose Cu$_2$ZnSiTe$_4$ to be a potential candidate for TE applications, and believe to attract future experimental/theoretical studies.

Structure and scaling of Kitaev chain across a quantum critical point in real space. (arXiv:2401.05954v1 [cond-mat.supr-con])
Yan He, Chih-Chun Chien

The spatial Kibble-Zurek mechanism (KZM) is applied to the Kitaev chain with inhomogeneous pairing interactions that vanish in half of the lattice and result in a quantum critical point separating the superfluid and normal-gas phases in real space. The weakly-interacting BCS theory predicts scaling behavior of the penetration of the pair wavefunction into the normal-gas region different from conventional power-law results due to the non-analytic dependence of the BCS order parameter on the interaction. The Bogoliubov-de Gennes (BdG) equation produces numerical results confirming the scaling behavior and hints complications in the strong-interaction regime. The limiting case of the step-function quench shows the dominance of the BCS coherence length in absence of additional length scale. Furthermore, the energy spectrum and wavefunctions from the BdG equation show abundant in-gap states from the normal-gas region in addition to the topological edge states.

Understanding how off-stoichiometry promotes cation mixing in LiNiO$_2$. (arXiv:2401.05983v1 [cond-mat.mtrl-sci])
Cem Komurcuoglu, Yunhao Xiao, Xinhao Li, Joaquin Rodriguez-Lopez, Zheng Li, Alan C. West, Alexander Urban

Although LiNiO$_2$ is chemically similar to LiCoO$_2$ and offers a nearly identical theoretical capacity, LiNiO$_2$ and related Co-free Ni-rich cathode materials suffer from degradation during electrochemical cycling that has prevented practical use in Li-ion batteries. The observed capacity decay of LiNiO$_2$ has been attributed to the formation of structural defects via Li/Ni cation mixing that reduces cyclability and leads to poor capacity retention. Herein, we investigate the kinetics and thermodynamics of Li/Ni mixing in ideal LiNiO$_2$ and off-stoichiometric Li$_{1-z}$Ni$_{1+z}$O$_2$. We find that ideal LiNiO$_2$ is stable against cation mixing with similar characteristics as LiCoO$_2$. Li/Ni mixing is promoted by extra Ni in the Li layers that cannot be avoided in synthesis. Our study elucidates the crucial role of extra Ni atoms on Li sites in the cation mixing mechanism, an insight that can inform the development of Co-free cathode materials.

Twisted TMDs in the small-angle limit: exponentially flat and trivial bands. (arXiv:2401.06078v1 [math-ph])
Simon Becker, Mengxuan Yang

Recent experiments discovered fractional Chern insulator states at zero magnetic field in twisted bilayer MoTe$_2$ [C23,Z23] and WSe$_2$ [MD23]. In this article, we study the MacDonald Hamiltonian for twisted transition metal dichalcogenides (TMDs) and analyze the low-lying spectrum in TMDs in the limit of small twisting angles. Unlike in twisted bilayer graphene Hamiltonians, we show that TMDs do not exhibit flat bands. The flatness in TMDs for small twisting angles is due to spatial confinement by a matrix-valued potential. We show that by generalizing semiclassical techniques developed by Simon [Si83] and Helffer-Sj\"ostrand [HS84] to matrix-valued potentials, there exists a wide range of model parameters such that the low-lying bands are of exponentially small width in the twisting angle, topologically trivial, and obey a harmonic oscillator-type spacing with explicit parameters.

A first-principles thermodynamic model for the Ba$\unicode{x2013}$Zr$\unicode{x2013}$S system in equilibrium with sulfur vapour. (arXiv:2401.06092v1 [cond-mat.mtrl-sci])
Prakriti Kayastha, Giulia Longo, Lucy D. Whalley

The chalcogenide perovskite BaZrS$_3$ has strong visible light absorption and high chemical stability, is nontoxic, and is made from earth-abundant elements. As such, it is a promising candidate material for application in optoelectronic technologies. However the synthesis of BaZrS$_3$ thin-films for characterisation and device integration remains a challenge. Here we use density functional theory and lattice dynamics to calculate the vibrational properties of elemental, binary and ternary materials in the Ba-Zr-S system. This is used to build a thermodynamic model for the stability of BaZrS$_3$, BaS$_x$, and ZrS$_x$ in equilibrium with sulfur gas, across a range of temperatures and sulfur partial pressures. We highlight that reaction thermodynamics are highly sensitive to sulfur allotrope and the extent of allotrope mixing. We use our model to predict the synthesis conditions in which BaZrS$_3$ and the intermediate compound BaS$_3$, which is associated with fast reaction kinetics, can form. At a moderate temperature of 500C we find that BaS$_3$ is stable at pressures above 3x10$^5$ Pa. We also find BaZrS$_3$ is stable against decomposition into sulfur-rich binaries up to at least 1x10$^7$ Pa. Our work provides insights into the chemistry of this promising material and suggests the experimental conditions required for the successful synthesis of BaZrS$_3$.

Jupyter widgets and extensions for education and research in computational physics and chemistry. (arXiv:2401.06113v1 [physics.ed-ph])
Dou Du, Taylor J. Baird, Sara Bonella, Giovanni Pizzi

Python and Jupyter are becoming increasingly popular tools for computational physics and chemistry research and education. Interactive notebooks are a precious tool for creating graphical user interfaces and teaching materials, and Jupyter widgets constitute the core of their interactive functionality. Packages and libraries which offer a broad range of widgets for general purposes exist, but the lack of specialized widgets for computational physics, chemistry and materials science implies significant time investments for the development of effective Jupyter notebooks for research and education in these domains. Here, we present custom Jupyter widgets that we have developed to target the needs of these research and teaching communities. These widgets constitute high quality interactive graphical components and can be employed, for example, as tools to visualize and manipulate data, or to explore different visual representations of concepts, illuminating the relationships existing between them. In addition, we discuss the JupyterLab extensions that we developed to modify the JupyterLab interface for an enhanced user experience when working with various applications within the targeted scientific domains.

Sliding friction and superlubricity of colloidal AFM probes coated by tribo-induced graphitic transfer layers. (arXiv:2210.01211v2 [cond-mat.mes-hall] UPDATED)
Renato Buzio, Andrea Gerbi, Cristina Bernini, Luca Repetto, Andrea Vanossi

Colloidal probe Atomic Force Microscopy (AFM) allows to explore sliding friction phenomena in graphite contacts of nominal lateral size up to hundreds of nanometers. It is known that contact formation involves tribo-induced material transfer of graphite flakes from the graphitic substrate to the colloidal probe. In this context, sliding states with nearly-vanishing friction, i.e. superlubricity, may set in. A comprehensive investigation of the transfer layer properties is mandatory to ascertain the origin of superlubricity. Here we explore the friction response of micrometric beads, of different size and pristine surface roughness, sliding on graphite under ambient conditions. We show that such tribosystems undergo a robust transition towards a low-adhesion, low-friction state dominated by mechanical interactions at one dominant tribo-induced nanocontact. Friction force spectroscopy reveals that the nanocontact can be superlubric or dissipative, in fact undergoing a load-driven transition from dissipative stick-slip to continuous superlubric sliding. This behavior is excellently described by the thermally-activated, single-asperity Prandtl-Tomlinson model. Our results indicate that upon formation of the transfer layer, friction depends on the energy landscape experienced by the topographically-highest tribo-induced nanoasperity. Consistently we find larger dissipation when the tribo-induced nanoasperity is sled against surfaces with higher atomic corrugation than graphite, like MoS2 and WS2, in prototypical Van der Waals layered hetero-junctions.

Adiabatic computing for optimal thermodynamic efficiency of information processing. (arXiv:2302.09957v2 [cond-mat.stat-mech] UPDATED)
Salambô Dago, Sergio Ciliberto, Ludovic Bellon

Landauer's principle makes a strong connection between information theory and thermodynamics by stating that erasing a one-bit memory at temperature $T_0$ requires an average energy larger than $W_{LB}=k_BT_0 \ln2$, with $k_B$ Boltzmann's constant. This tiny limit has been saturated in model experiments using quasi-static processes. For faster operations, an overhead proportional to the processing speed and to the memory damping appears. In this article, we show that underdamped systems are a winning strategy to reduce this extra energetic cost. We prove both experimentally and theoretically that, in the limit of vanishing dissipation mechanisms in the memory, the physical system is thermally insulated from its environment during fast erasures, i.e. fast protocols are adiabatic as no heat is exchanged with the bath. Using a fast optimal erasure protocol we also show that these adiabatic processes produce a maximum adiabatic temperature $T_a=2T_0$, and that Landauer's bound for fast erasures in underdamped systems becomes the adiabatic bound: $W_a = k_B T_0$.

Emergent Energy Dissipation in Quantum Limit. (arXiv:2303.07692v2 [cond-mat.mes-hall] UPDATED)
Hailong Li, Hua Jiang, Qing-Feng Sun, X. C. Xie

Energy dissipation is of fundamental interest and crucial importance in quantum systems. However, whether energy dissipation can emerge inside topological systems remains a question, especially when charge transport is topologically protected and quantized. As a hallmark, we propose a microscopic picture that illustrates energy dissipation in the quantum Hall (QH) plateau regime of graphene. Despite the quantization of Hall, longitudinal, and two-probe resistances (dubbed as the quantum limit), we find that the energy dissipation emerges in the form of Joule heat. By analyzing the energy distribution of electrons, it is found that electrons can evolve between equilibrium and non-equilibrium without inducing extra two-probe resistance. The relaxation of non-equilibrium electrons results in the dissipation of energy along the QH edge states. Eventually, we suggest probing the phenomenon by measuring local temperature increases in experiments and reconsidering the dissipation typically ignored in realistic topological circuits.

Chiral anomaly and positive longitudinal magnetoresistance in the type-II Dirac semimetals $\it{A}_x$PdTe$_2$ (\textit{A} = Cu, Ag). (arXiv:2303.18075v2 [cond-mat.str-el] UPDATED)
Sonika, Sunil Gagwar, Nikhlesh Singh Mehta, G. Sharma, C.S.Yadav

The Planar Hall effect (PHE) in topological materials has been a subject of great interest in recent years. Generally, it is understood to originate from the chiral-anomaly (CA) induced charge pumping between doubly degenerate Weyl nodes. However, the occurrence of PHE in the materials with positive and anisotropic orbital magnetoresistance has raised questions about CA being the sole origin of this effect. Here, we report the PHE, magnetoresistance, and thermal transport properties (Seebeck and Nernst coefficients) on the Ag intercalated PdTe$_2$. We observe positive longitudinal magnetoresistance, the linear field dependence of the amplitude of PHE, and a prolate pattern in the parametric plots. The planar Hall resistivity and anisotropic magnetoresitance fits well with theoretical study of CA being the origin of PHE. So, our observations are consistent with Weyl physics dominating the PHE in PdTe$_2$, Cu$_{0.05}$PdTe$_2$, and Ag$_{0.05}$PdTe$_2$. We further support our data with a theoretical model that reproduces the qualitative experimental features. In addition, we have calculated the Seebeck ($\it{S}$) and Nernst ($\nu$) coefficients for PdTe$_2$ and Cu and Ag intercalated compounds. The estimated values of Fermi energy for the Cu and Ag intercalated compounds are respectively two times and three times larger than that of PdTe$_2$.

Effect of interatomic repulsion on Majorana zero modes in a coupled quantum-dot-superconducting-nanowire hybrid system. (arXiv:2309.10888v3 [cond-mat.mes-hall] UPDATED)
R. Kenyi Takagui Perez, A. A. Aligia

We study the low-energy eigenstates of a topological superconductor wire modeled by a Kitaev chain, which is connected at one of its ends to a quantum dot through nearest-neighbor (NN) hopping and NN Coulomb repulsion. Using an unrestricted Hartree-Fock approximation to decouple the Coulomb term, we obtain that the quality of the Majorana end states is seriously affected by this term only when the dependence of the low-lying energies with the energy of the quantum dot shows a "diamond" shape, characteristic of short wires. We discuss limitations of the simplest effective models to describe the physics. We expect the same behavior in more realistic models for topological superconducting wires.

Machine Eye for Defects: Machine Learning-Based Solution to Identify and Characterize Topological Defects in Textured Images of Nematic Materials. (arXiv:2310.06406v2 [cond-mat.soft] UPDATED)
Haijie Ren, Weiqiang Wang, Wentao Tang, Rui Zhang

Topological defects play a key role in the structures and dynamics of liquid crystals (LCs) and other ordered systems. There is a recent interest in studying defects in different biological systems with distinct textures. However, a robust method to directly recognize defects and extract their structural features from various traditional and nontraditional nematic systems remains challenging to date. Here we present a machine learning solution, termed Machine Eye for Defects (MED), for automated defect analysis in images with diverse nematic textures. MED seamlessly integrates state-of-the-art object detection networks, Segment Anything Model, and vision transformer algorithms with tailored computer vision techniques. We show that MED can accurately identify the positions, winding numbers, and orientations of $\pm 1/2$ defects across distinct cellular contours, sparse vector fields of nematic directors, actin filaments, microtubules, and simulation images of Gay--Berne particles. MED performs faster than conventional defect detection method and can achieve over 90\% accuracy on recognizing $\pm1/2$ defects and their orientations from vector fields and experimental tissue images. We further demonstrate that MED can identify defect types that are not included in the training data, such as giant-core defects and defects with higher winding number. Remarkably, MED provides correct structural information about $\pm 1$ defects, i.e., the phase angle for $+1$ defects and the orientation angle for $-1$ defects. As such, MED stands poised to transform studies of diverse ordered systems by providing automated, rapid, accurate, and insightful defect analysis.

Holographic $a$-functions and Boomerang RG Flows. (arXiv:2310.15983v2 [hep-th] UPDATED)
Elena Cáceres, Rodrigo Castillo Vásquez, Karl Landsteiner, Ignacio Salazar Landea

We use the radial null energy condition to construct a monotonic $a$-function for a certain type of non-relativistic holographic RG flows. We test our $a$-function in three different geometries that feature a Boomerang RG flow, characterized by a domain wall between two AdS spaces with the same AdS radius, but with different (and sometimes directions dependent) speeds of light. We find that the $a$-function monotonically decreases and goes to a constant in the asymptotic regimes of the geometry. Using the holographic dictionary in this asymptotic AdS spaces, we find that the $a$-function not only reads the fixed point central charge but also the speed of light, suggesting what the correct RG charge might be for non-relativistic RG flows.

Electrically tunable correlated domain wall network in twisted bilayer graphene. (arXiv:2311.14384v2 [cond-mat.mes-hall] UPDATED)
Hao-Chien Wang, Chen-Hsuan Hsu

We investigate the domain wall network in twisted bilayer graphene (TBG) under the influence of interlayer bias and screening effect from the layered structure. Starting from the continuum model, we analyze the low-energy domain wall modes within the moir\'e bilayer structure and obtain an analytic form representing charge density distributions of the two-dimensional structure. By computing the screened electron-electron interaction strengths both within and between the domain walls, we develop a bosonized model that describes the correlated domain wall network. We demonstrate that these interaction strengths can be modified through an applied interlayer bias, screening length and dielectric materials, and show how the model can be employed to investigate various properties of the domain wall network and its stability. We compute correlation functions both without and with phonons. Including electron-phonon coupling in the network, we establish phase diagrams from these correlation functions. These diagrams illustrate electrical tunability of the network between various phases, such as density wave states and superconductivity. Our findings reveal the domain wall network as a promising platform for the experimental manipulation of electron-electron interactions in low dimensions and the study of strongly correlated matter. We point out that our investigation not only enhances the understanding of domain wall modes in TBG but also has broader implications for the development of moir\'e devices.

Topological Phase Transition without Single-Particle-Gap Closing in Strongly Correlated Systems. (arXiv:2401.01402v2 [cond-mat.str-el] UPDATED)
Peizhi Mai, Jinchao Zhao, Thomas A. Maier, Barry Bradlyn, Philip W. Phillips

We show here that numerous examples abound where changing topology does not necessarily close the bulk insulating charge gap as demanded in the standard non-interacting picture. From extensive determinantal and dynamical cluster quantum Monte Carlo simulations of the half-filled and quarter-filled Kane-Mele-Hubbard model, we show that for sufficiently strong interactions at either half- or quarter-filling, a transition between topological and trivial insulators occurs without the closing of a charge gap. To shed light on this behavior, we illustrate that an exactly solvable model reveals that while the single-particle gap remains, the many-body gap does in fact close. These two gaps are the same in the non-interacting system but depart from each other as the interaction turns on. We purport that for interacting systems, the proper probe of topological phase transitions is the closing of the many-body rather than the single-particle gap.

Found 10 papers in prb
Date of feed: Fri, 12 Jan 2024 04:17:04 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)

Local Chern marker for periodic systems
Nicolas Baù and Antimo Marrazzo
Author(s): Nicolas Baù and Antimo Marrazzo

Topological invariants are global properties of the ground-state wave function, typically defined as winding numbers in reciprocal space. Over the years, a number of topological markers in real space have been introduced, allowing to map topological order in heterogeneous crystalline and disordered …

[Phys. Rev. B 109, 014206] Published Thu Jan 11, 2024

Oscillating edge states in polariton topological insulators
Chunyan Li and Yaroslav V. Kartashov
Author(s): Chunyan Li and Yaroslav V. Kartashov

We show that slow time-periodic variation of the external magnetic field applied to a polariton topological insulator based on a honeycomb array of microcavity pillars with pronounced TE-TM splitting results in oscillations of the edge states along the boundary of the insulator accompanied by slow t…

[Phys. Rev. B 109, 014307] Published Thu Jan 11, 2024

Electronic structure and magnetic and transport properties of antiferromagnetic Weyl semimetal GdAlSi
Antu Laha, Asish K. Kundu, Niraj Aryal, Emil S. Bozin, Juntao Yao, Sarah Paone, Anil Rajapitamahuni, Elio Vescovo, Tonica Valla, Milinda Abeykoon, Ran Jing, Weiguo Yin, Abhay N. Pasupathy, Mengkun Liu, and Qiang Li
Author(s): Antu Laha, Asish K. Kundu, Niraj Aryal, Emil S. Bozin, Juntao Yao, Sarah Paone, Anil Rajapitamahuni, Elio Vescovo, Tonica Valla, Milinda Abeykoon, Ran Jing, Weiguo Yin, Abhay N. Pasupathy, Mengkun Liu, and Qiang Li

We report the topological electronic structure and magnetic and magnetotransport properties of a noncentrosymmetric compound GdAlSi. Magnetic susceptibility shows an antiferromagnetic transition at ${T}_{\mathrm{N}}=32$ K. In-plane isothermal magnetization exhibits an unusual hysteresis behavior at …

[Phys. Rev. B 109, 035120] Published Thu Jan 11, 2024

Discovering two-dimensional magnetic topological insulators by machine learning
Haosheng Xu, Yadong Jiang, Huan Wang, and Jing Wang
Author(s): Haosheng Xu, Yadong Jiang, Huan Wang, and Jing Wang

Topological materials with unconventional electronic properties have been investigated intensively for both fundamental and practical interests. Thousands of topological materials have been identified by symmetry-based analysis and ab initio calculations. However, the predicted magnetic topological …

[Phys. Rev. B 109, 035122] Published Thu Jan 11, 2024

Transient absorption measurements of excitonic dynamics in $3R\text{−}{\mathrm{MoS}}_{2}$
Gbenga Agunbiade, Neema Rafizadeh, Ryan J. Scott, and Hui Zhao
Author(s): Gbenga Agunbiade, Neema Rafizadeh, Ryan J. Scott, and Hui Zhao

The excitonic dynamics in ${\mathrm{MoS}}_{2}$ monolayer, bilayer, and bulk flakes with different stacking orders, namely $3R$ and $2H$, are investigated through transient absorption spectroscopy at room temperature. Samples are obtained by the mechanical exfoliation of bulk ${\mathrm{MoS}}_{2}$ cry…

[Phys. Rev. B 109, 035410] Published Thu Jan 11, 2024

Spin waves in bilayers of transition metal dichalcogenides
Wojciech Rudziński, Józef Barnaś, and Anna Dyrdał
Author(s): Wojciech Rudziński, Józef Barnaś, and Anna Dyrdał

Van der Waals magnetic materials are currently of great interest as materials for applications in future ultrathin nanoelectronics and nanospintronics. Due to weak coupling between individual monolayers, these materials can be easily obtained in the monolayer and bilayer forms. The latter are of spe…

[Phys. Rev. B 109, 035412] Published Thu Jan 11, 2024

Topological density correlations in a Fermi gas
Pok Man Tam and Charles L. Kane
Author(s): Pok Man Tam and Charles L. Kane

A Fermi gas of noninteracting electrons, or ultracold fermionic atoms, has a quantum ground state defined by a region of occupancy in momentum space known as the Fermi sea. The Euler characteristic ${χ}_{F}$ of the Fermi sea serves to topologically classify these gapless fermionic states. The topolo…

[Phys. Rev. B 109, 035413] Published Thu Jan 11, 2024

Twisted topology of non-Hermitian systems induced by long-range coupling
S. M. Rafi-Ul-Islam, Zhuo Bin Siu, Haydar Sahin, Md. Saddam Hossain Razo, and Mansoor B. A. Jalil
Author(s): S. M. Rafi-Ul-Islam, Zhuo Bin Siu, Haydar Sahin, Md. Saddam Hossain Razo, and Mansoor B. A. Jalil

We investigate the twisted topology of the complex eigenspectrum of a one-dimensional non-Hermitian system under the influence of long-range unidirectional coupling. Unlike the complex energy spectrum of the conventional Hatano-Nelson chain, which takes the form of a single loop with a topological w…

[Phys. Rev. B 109, 045410] Published Thu Jan 11, 2024

Electrical manipulation of valley qubit and valley geometric phase in lateral monolayer heterostructures
Jarosław Pawłowski, John Eric Tiessen, Rockwell Dax, and Junxia Shi
Author(s): Jarosław Pawłowski, John Eric Tiessen, Rockwell Dax, and Junxia Shi

We explore a solid-state qubit defined on valley isospin of an electron confined in a gate-defined quantum dot created in an area of monolayer ${\mathrm{MoS}}_{2}/{\mathrm{WS}}_{2}$ lateral junction where a steep dipolar potential emerges. We show that the junction oriented along an armchair directi…

[Phys. Rev. B 109, 045411] Published Thu Jan 11, 2024

Quantum coherent control of linear and nonlinear thermoelectricity in graphene nanostructure heat engines
Yuga Kodama and Nobuhiko Taniguchi
Author(s): Yuga Kodama and Nobuhiko Taniguchi

We theoretically show how structural modifications and controlling quantum coherency can enhance linear and nonlinear thermoelectric performance in graphene nanostructure heat engines. Although graphene has emerged as a promising material for a nanoscale heat engine due to its high coherency and tun…

[Phys. Rev. B 109, 045412] Published Thu Jan 11, 2024

Found 3 papers in prl
Date of feed: Fri, 12 Jan 2024 04:17:02 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)

Ginzburg-Landau Theory of Flat-Band Superconductors with Quantum Metric
Shuai A. Chen and K. T. Law
Author(s): Shuai A. Chen and K. T. Law

An application of Ginzburg-Landau theory to superconducting twisted bilayer graphene determines the coherence length and the upper critical field, which are in agreement with recent experiments.

[Phys. Rev. Lett. 132, 026002] Published Thu Jan 11, 2024

Nernst Sign Reversal in the Hexatic Vortex Phase of Weakly Disordered $a\text{−}\mathrm{MoGe}$ Thin Films
Y. Wu, A. Roy, S. Dutta, J. Jesudasan, P. Raychaudhuri, and A. Frydman
Author(s): Y. Wu, A. Roy, S. Dutta, J. Jesudasan, P. Raychaudhuri, and A. Frydman

The hexatic phase is an intermediate stage in the melting process of a 2D crystal due to topological defects. Recently, this exotic phase was experimentally identified in the vortex lattice of 2D weakly disordered superconducting MoGe by scanning tunneling microscopic measurements. Here, we study th…

[Phys. Rev. Lett. 132, 026003] Published Thu Jan 11, 2024

Dynamical Control of Topology in Polar Skyrmions via Twisted Light
Lingyuan Gao, Sergei Prokhorenko, Yousra Nahas, and Laurent Bellaiche
Author(s): Lingyuan Gao, Sergei Prokhorenko, Yousra Nahas, and Laurent Bellaiche

Twisted light carries a nonzero orbital angular momentum, that can be transferred from light to electrons and particles ranging from nanometers to micrometers. Up to now, the interplay between twisted light with dipolar systems has scarcely been explored, though the latter bear abundant forms of top…

[Phys. Rev. Lett. 132, 026902] Published Thu Jan 11, 2024

Found 4 papers in pr_res
Date of feed: Fri, 12 Jan 2024 04:17:02 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)

Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr effect
Dusan Lorenc and Zhanybek Alpichshev
Author(s): Dusan Lorenc and Zhanybek Alpichshev

It is a basic principle that an effect cannot come before the cause. Dispersive relations that follow from this fundamental fact have proven to be an indispensable tool in physics and engineering. They are most powerful in the domain of linear response where they are known as Kramers-Kronig relation…

[Phys. Rev. Research 6, 013042] Published Thu Jan 11, 2024

Detecting fractionalization in critical spin liquids using color centers
So Takei and Yaroslav Tserkovnyak
Author(s): So Takei and Yaroslav Tserkovnyak

Quantum spin liquids are highly entangled ground states of insulating spin systems, in which magnetic ordering is prevented down to the lowest temperatures due to quantum fluctuations. One of the most extraordinary characteristics of quantum spin liquid phases is their ability to support fractionali…

[Phys. Rev. Research 6, 013043] Published Thu Jan 11, 2024

Interstate Berry curvature of hinge state and its detection
Zheng Liu, Zhenhua Qiao, Yang Gao, and Qian Niu
Author(s): Zheng Liu, Zhenhua Qiao, Yang Gao, and Qian Niu

The localized hinge state of the second-order topological insulator can have a non-Abelian Berry curvature component, which can be detected by a circular photogalvanic effect, with light illuminating a specific hinge. The optical sum rule can further reflect the interstate Berry curvature between the hinge state and the ground state.

[Phys. Rev. Research 6, L012005] Published Thu Jan 11, 2024

Pauli blockade catalogue and three- and four-particle Kondo effect in bilayer graphene quantum dots
Chuyao Tong, Annika Kurzmann, Rebekka Garreis, Kenji Watanabe, Takashi Taniguchi, Thomas Ihn, and Klaus Ensslin
Author(s): Chuyao Tong, Annika Kurzmann, Rebekka Garreis, Kenji Watanabe, Takashi Taniguchi, Thomas Ihn, and Klaus Ensslin

In bilayer graphene, a comprehensive catalog of double quantum dot Pauli blockade for up to four carriers per dot is established, revealing a more complex transition structure than in conventional systems due to the involvement of both spin and valley pseudospin degrees of freedom. This result provides new possibilities for spin and valley qubit manipulation and control in bilayer graphene.

[Phys. Rev. Research 6, L012006] Published Thu Jan 11, 2024

Found 1 papers in nano-lett
Date of feed: Thu, 11 Jan 2024 14:07:21 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)

[ASAP] Exploiting Topological Darkness in Photonic Crystal Slabs for Spatiotemporal Vortex Generation
Wenzhe Liu, Jiajun Wang, Yang Tang, Xinhao Wang, Xingqi Zhao, Lei Shi, Jian Zi, and C. T. Chan

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.3c04348

Found 3 papers in comm-phys

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)

Automatically discovering ordinary differential equations from data with sparse regression
Rui Carvalho

Communications Physics, Published online: 09 January 2024; doi:10.1038/s42005-023-01516-2

Discovering nonlinear differential equations from empirical data is a significant challenge, often requiring manual parameter tuning. This paper introduces a machine learning method integrating denoising techniques, sparse regression, and bootstrap confidence intervals, which shows consistent accuracy in identifying 3D dynamical systems with moderate data size and high signal quality.

Topological phase transitions of generalized Brillouin zone
Moon Jip Park

Communications Physics, Published online: 09 January 2024; doi:10.1038/s42005-024-01519-7

A key problem in non-Hermitian lattice physics is restoring bulk-boundary correspondence. Here, the authors study two non-Hermitian models with a generalized boundary condition, proving that these systems can continuously be tuned from a periodic to an open boundary condition, showing a phase transition characterized by an exceptional point.

Generating fine-grained surrogate temporal networks
B. Lepri

Communications Physics, Published online: 09 January 2024; doi:10.1038/s42005-023-01517-1

Surrogate networks are synthetic alternatives to real world networks that avoid expensive data collection and privacy issues, but they often lack information on the temporal or topological properties of the input network. The authors propose a method to construct realistic surrogate network, outperforming the existing ones in accuracy and execution time.

Found 1 papers in scipost

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)

Hidden symmetry of Bogoliubov de Gennes quasi-particle eigenstates and universal relations in flat band superconducting bipartite lattices, by G. Bouzerar, M. Thumin
< author missing >
Submitted on 2024-01-11, refereeing deadline 2024-02-16.