Found 34 papers in cond-mat
Date of feed: Thu, 21 Sep 2023 00:30:00 GMT

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Anomalous crystalline-electromagnetic responses in semimetals. (arXiv:2309.10840v1 [cond-mat.mes-hall])
Mark R. Hirsbrunner, Oleg Dubinkin, Fiona J. Burnell, Taylor L. Hughes

We present a unifying framework that allows us to study the mixed crystalline-electromagnetic responses of topological semimetals in spatial dimensions up to $D = 3$ through dimensional augmentation and reduction procedures. We show how this framework illuminates relations between the previously known topological semimetals, and use it to identify a new class of quadrupolar nodal line semimetals for which we construct a lattice tight-binding Hamiltonian. We further utilize this framework to quantify a variety of mixed crystalline-electromagnetic responses, including several that have not previously been explored in existing literature, and show that the corresponding coefficients are universally proportional to weighted momentum-energy multipole moments of the nodal points (or lines) of the semimetal. We introduce lattice gauge fields that couple to the crystal momentum and describe how tools including the gradient expansion procedure, dimensional reduction, compactification, and the Kubo formula can be used to systematically derive these responses and their coefficients. We further substantiate these findings through analytical physical arguments, microscopic calculations, and explicit numerical simulations employing tight-binding models.

Effect of interatomic repulsion on Majorana zero modes in a coupled quantum-dot-superconducting-nanowire hybrid system. (arXiv:2309.10888v1 [cond-mat.mes-hall])
R. Kenyi Takagui Perez, A. A. Aligia, Centro Atomico Bariloche, Instituto Balseiro

We study the low-energy eigenstates of a topological superconductor wire modeled by a Kitaev chain coupled at one of its ends to a quantum dot by 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.

Anomalous microwave response in the dissipative regime of topological superconducting devices based on Bi2Te2.3Se0.7. (arXiv:2309.10897v1 [cond-mat.supr-con])
Vasily Stolyarov, Sergei Kozlov, Dmitry Yakovlev, Nicolas Bergeal, Cheryl Feuillet-Palma, Dmitry Lvov, Olga Skryabina, Mikhail Kupriyanov, Alexander Golubov, Dimitri Roditchev

Superconducting proximity junctions based on topological insulators are widely believed to harbor Majorana-like bound states. The latter serves as a paradigm non-local topological quantum computation protocols. Nowadays, a search for topological phases in different materials, perspective for a realization of topological qubits, is one of the central efforts in quantum physics. It is motivated, in particular, by recent observation of anomalous ac Josephson effect, which being a signature of Majorana physics. Its manifestations, such as a fractional Josephson frequency and the absence of the first (or several odd in more rare cases), Shapiro steps, were reported for different materials. Here we study Shapiro steps in Nb/Bi2Te2.3Se0.7/Nb junctions, based on ultrasmall single crystals of a 3D topological insulator synthesized by a physical vapor deposition (PVD) technique. We present evidence that our junctions are ballistic. When subjected to microwave radiation, the junctions exhibit Shapiro steps, but the first step is missing. Typically it is assumed that the missing first step (MFS) effect cannot be observed in the presence of quasiparticle poisoning due to suppression of the 4{\pi}-periodic component. Our findings within the context of the RSJ-model of Josephson junction dynamics show that such behaviour of samples corresponds to a specific condition, requiring a minimum of 5% of the 4{\pi}-component for disappearance of the first Shapiro step.

Impact of micro-indentation load/time and Zinc concentration on the thermo-mechanical characteristics of amorphous Se$_{78}$Te$_{20}$Sn$_2$ alloy. (arXiv:2309.10915v1 [cond-mat.mtrl-sci])
Vishnu Saraswat A. Dahshan, H. I. Elsaeedy, Neeraj Mehta

We have performed hardness measurement experiments under different loads and loading times by performing micro-indentation marks in the present work. Chalcogenide glasses (ChGs) comprising Se$_{78}$Te$_{20}$Sn$_2$ and Se$_{78-x}$Te$_{20}$Sn$_2$Zn$_x$ (where $x = 0, 2, 4, 6$) alloys are the subject of micro-indentation tests in this work. We have utilized both micro-indentation and optical microscopic methods to determine Vickers hardness. Thermal glass transition phenomena have been identified through DSC techniques. The modulus of elasticity (E), an essential mechanical property, has been evaluated using established empirical equations. Further, we have studied other mechanical parameters [e.g., minimal micro-void formation energy (Eh), glass's fragility index (m), micro-void volume (Vh), etc.] and the covalent character of the glassy system. Additionally, various physical parameters, including density, molar volume, and compactness, have also been determined.

Biaxial Strain Enhances Electron Mobility of Monolayer Transition Metal Dichalcogenides. (arXiv:2309.10939v1 [cond-mat.mes-hall])
Jerry Austin Yang, Robert Kevin Arran Bennett, Lauren Hoang, Zhepeng Zhang, Kamila Jewell Thompson, Andrew Jacob Mannix, E. Pop

Strain engineering can modulate the material properties of two-dimensional (2D) semiconductors for electronic and optoelectronic applications. Recent theory and experiments have found that uniaxial tensile strain can improve the electron mobility of monolayer MoS$_2$, a 2D semiconductor, but the effects of biaxial strain on charge transport are not well-understood in 2D semiconductors. Here, we use biaxial tensile strain on flexible substrates to probe the electron mobility in monolayer WS$_2$ and MoS$_2$ transistors. This approach experimentally achieves ~2x higher on-state current and mobility with ~0.3% applied biaxial strain in WS$_2$, the highest mobility improvement at the lowest strain reported to date. We also examine the mechanisms behind this improvement through density functional theory simulations, concluding that the enhancement is primarily due to reduced intervalley electron-phonon scattering. These results underscore the role of strain engineering 2D semiconductors for flexible electronics, sensors, integrated circuits, and other opto-electronic applications.

Revealing the conduction band and pseudovector potential in 2D moir\'e semiconductors. (arXiv:2309.10964v1 [cond-mat.mes-hall])
Abigail J. Graham, Heonjoon Park, Paul V. Nguyen, James Nunn, Viktor Kandyba, Mattia Cattelan, Alessio Giampietri, Alexei Barinov, Kenji Watanabe, Takashi Taniguchi, Anton Andreev, Mark Rudner, Xiaodong Xu, Neil R. Wilson, David H. Cobden

Stacking monolayer semiconductors results in moir\'e patterns that host many correlated and topological electronic phenomena, but measurements of the basic electronic structure underpinning these phenomena are scarce. Here, we investigate the properties of the conduction band in moir\'e heterobilayers using submicron angle-resolved photoemission spectroscopy with electrostatic gating, focusing on the example of WS2/WSe2. We find that at all twist angles the conduction band edge is the K-point valley of the WS2, with a band gap of 1.58 +- 0.03 eV. By resolving the conduction band dispersion, we observe an unexpectedly small effective mass of 0.15 +- 0.02 m_e. In addition, we observe replicas of the conduction band displaced by reciprocal lattice vectors of the moir\'e superlattice. We present arguments and evidence that the replicas are due to modification of the conduction band states by the moir\'e potential rather than to final-state diffraction. Interestingly, the replicas display an intensity pattern with reduced, 3-fold symmetry, which we show implicates the pseudo vector potential associated with in-plane strain in moir\'e band formation.

Gauge Theories of Josephson Junction Arrays: Why Disorder Is Irrelevant for the Electric Response of Disordered Superconducting Films. (arXiv:2309.11098v1 [cond-mat.supr-con])
Carlo A. Trugenberger

We review the topological gauge theory of Josephson junction arrays and thin film superconductors, stressing the role of the usually forgotten quantum phase slips, and we derive their quantum phase structure. A quantum phase transition from a superconducting to the dual, superinsulating phase with infinite resistance (even at finite temperatures) is either direct or goes through an intermediate bosonic topological insulator phase, which is typically also called Bose metal. We show how, contrary to a widely held opinion, disorder is not relevant for the electric response in these quantum phases because excitations in the spectrum are either symmetry-protected or neutral due to confinement. The quantum phase transitions are driven only by the electric interaction growing ever stronger. First, this prevents Bose condensation, upon which out-of-condensate charges and vortices form a topological quantum state owing to mutual statistics interactions. Then, at even stronger couplings, an electric flux tube dual to Abrikosov vortices induces a linearly confining potential between charges, giving rise to superinsulation.

Electrostatic environment and Majorana bound states in full-shell topological insulator nanowires. (arXiv:2309.11149v1 [cond-mat.mes-hall])
Li Chen, Xiao-Hong Pan, Zhan Cao, Dong E. Liu, Xin Liu

The combination of a superconductor (SC) and a topological insulator (TI) nanowire was proposed as a potential candidate for realizing Majorana zero modes (MZMs). In this study, we adopt the Schr\"odinger-Poisson formalism to incorporate the electrostatic environment inside the nanowire and systematically explore its topological properties. Our calculations reveal that the proximity to the SC induces a band bending effect, leading to a non-uniform potential across the TI nanowire. As a consequence, there is an upward shift of the Fermi level within the conduction band. This gives rise to the coexistence of surface and bulk states, localized in an accumulation layer adjacent to the TI-SC interface. When magnetic flux is applied, these occupied states have different flux-penetration areas, suppressing the superconducting gap. However, this impact can be mitigated by increasing the radius of the nanowire. Finally, We demonstrate that MZMs can be achieved across a wide range of parameters centered around one applied flux quantum, $\phi_0 = h/2e$. Within this regime, MZMs can be realized even in the presence of conduction bands, which are not affected by the band bending effect. These findings provide valuable insights into the practical realization of MZMs in TI nanowire-based devices, especially in the presence of a complicated electrostatic environment.

Evaluating Gilbert Damping in Magnetic Insulators from First Principles. (arXiv:2309.11152v1 [cond-mat.mtrl-sci])
Liangliang Hong, Changsong Xu, Hongjun Xiang

Magnetic damping has a significant impact on the performance of various magnetic and spintronic devices, making it a long-standing focus of research. The strength of magnetic damping is usually quantified by the Gilbert damping constant in the Landau-Lifshitz-Gilbert equation. Here we propose a first-principles based approach to evaluate the Gilbert damping constant contributed by spin-lattice coupling in magnetic insulators. The approach involves effective Hamiltonian models and spin-lattice dynamics simulations. As a case study, we applied our method to Y$_3$Fe$_5$O$_{12}$, MnFe$_2$O$_4$ and Cr$_2$O$_3$. Their damping constants were calculated to be $0.8\times10^{-4}$, $0.2\times10^{-4}$, $2.2\times 10^{-4}$, respectively at a low temperature. The results for Y$_3$Fe$_5$O$_{12}$ and Cr$_2$O$_3$ are in good agreement with experimental measurements, while the discrepancy in MnFe$_2$O$_4$ can be attributed to the inhomogeneity and small band gap in real samples. The stronger damping observed in Cr$_2$O$_3$, compared to Y$_3$Fe$_5$O$_{12}$, essentially results from its stronger spin-lattice coupling. In addition, we confirmed a proportional relationship between damping constants and the temperature difference of subsystems, which had been reported in previous studies. These successful applications suggest that our approach serves as a promising candidate for estimating the Gilbert damping constant in magnetic insulators.

Generalized Kohn-Sham Approach for the Electronic Band Structure of Spin-Orbit Coupled Materials. (arXiv:2309.11158v1 [cond-mat.mtrl-sci])
Jacques K. Desmarais, Giacomo Ambrogio, Giovanni Vignale, Alessandro Erba, Stefano Pittalis

Spin-current density functional theory (SCDFT) is a formally exact framework designed to handle the treatment of interacting many-electron systems including spin-orbit coupling at the level of the Pauli equation. In practice, robust and accurate calculations of the electronic structure of these systems call for functional approximations that depend not only on the densities, but also on spin-orbitals. Here we show that the call can be answered by resorting to an extension of the Kohn-Sham formalism, which admits the use of non-local effective potentials, yet it is firmly rooted in SCDFT. The power of the extended formalism is demonstrated by calculating the spin-orbit-induced band-splittings of inversion-asymmetric MoSe$_2$ monolayer and inversion-symmetric bulk $\alpha$-MoTe$_2$. We show that quantitative agreement with experimental data is obtainable via global hybrid approximations by setting the fraction of Fock exchange at the same level which yields accurate values of the band gap. Key to these results is the ability of the method to self-consistently account for the spin currents induced by the spin-orbit interaction. The widely used method of refining spin-density functional theory by a second-variational treatment of spin-orbit coupling is unable to match our SCDFT results.

Composition-dependent absorption of radiation in semiconducting MSi2Z4 Monolayers. (arXiv:2309.11163v1 [cond-mat.mtrl-sci])
Muhammad Sufyan Ramzan, Tomasz Woźniak, Agnieszka Kuc, Caterina Cocchi

The recent synthesis of MoSi2N4 material, along with theoretical predictions encompassing the entire family of chemical analogs, has opened up a new array of low-dimensional materials for a diverse range of optoelectronics and photovoltaics applications. In this study, we conducted state-of-the-art many-body first-principles calculations to analyze the quasi-particle electronic structure of the material class MSi2Z4 (where M = Mo, W, and Z = N, P, As, Sb). All monolayers display a direct band gap at the K point, with the exception of MoSi2N4. In tungsten-based compounds, the fundamental-gap can be adjusted over a significantly broader energy range compared to their molybdenum-based counterparts. Additionally, increasing atomic weight of the Z, both the band gap and exciton binding energies decrease. A noteworthy feature is the absence of a lateral valley ({\Lambda} or Q) near the conduction band minimum, indicating potential higher photoluminescence efficiencies compared to conventional transition-metal dichalcogenide monolayers. The optical spectra of these materials are predominantly characterized by tightly bound excitons, leading to an absorption onset in the visible range (for N-based) and in the infrared region (for others). This diversity offers promising opportunities to incorporate these materials and their heterostructures into optoelectronic devices, with tandem solar cells being particularly promising.

Universal direction in thermoosmosis of a near-critical binary fluid mixture. (arXiv:2309.11208v1 [cond-mat.soft])
Shunsuke Yabunaka, Youhei Fujitani

We consider thermoosmosis of a near-critical binary fluid mixture, lying in the one-phase region, through a capillary tube in the presence of preferential adsorption of one component. The critical composition is assumed in the two reservoirs linked by the tube. With coarse-grained approach, we evaluate the flow field induced by the thermal force density. We predict a universal property; if the mixture is near the upper (lower) consolute point, the flow direction is the same as (opposite to) the direction of the temperature gradient, irrespective of which component is adsorbed onto the wall.

Thermoosmosis of a near-critical binary fluid mixture: a general formulation and universal flow direction. (arXiv:2309.11211v1 [cond-mat.soft])
Youhei Fujitani, Shunsuke Yabunaka

We consider a binary fluid mixture, which lies in the one-phase region near the demixing critical point, and study its transport through a capillary tube linking two large reservoirs. We assume that short-range interactions cause preferential adsorption of one component on the tube's wall. The adsorption layer can become much thicker than the molecular size, which enables us to apply hydrodynamics based on a coarse-grained free-energy functional. For linear transport phenomena induced by gradients of the pressure, composition, and temperature along a cylindrical tube, we obtain the formulas of the Onsager coefficients to extend our previous results on isothermal transport, assuming the critical composition in the middle of each reservoir in the reference equilibrium state. Among the linear transport phenomena, we focus on thermoosmosis -- mass flow due to a temperature gradient. We explicitly derive a formula for the thermal force density, which is nonvanishing in the adsorption layer and causes thermoosmosis. This formula for a near-critical binary fluid mixture is an extension of the conventional formula for a one-component fluid, expressed in terms of local excess enthalpy. We predict that the direction of thermoosmotic flow of a mixture near the upper (lower) consolute point is the same as (opposite to) that of the temperature gradient, irrespective of which component is adsorbed on the wall. Our procedure would also be applied to dynamics of a soft material, whose mesoscopic inhomogeneity can be described by a coarse-grained free-energy functional.

Origin of the gap in the surface states of the antiferromagnetic topological insulator. (arXiv:2309.11216v1 [cond-mat.mes-hall])
R. S. Akzyanov, A. L. Rakhmanov

We study the influence of the antiferromagnetic order on the surface states of topological insulators. We derive an effective Hamiltonian for these states, taking into account the space structure of the antiferromagnetic ordering. We obtain a typical (gapless) Dirac Hamiltonian for the surface states if the surface of the sample is not perturbed. However, a shift in the chemical potential of the surface layer opens a gap in the spectrum away from Fermi energy. Such a gap arises only in systems with a finite antiferromagnetic order. We observe that the gap is robust against the surface disorder. The obtained results are consistent with the recent experiments and density functional theory calculations.

Atomic-scale visualization of multiferroicity in monolayer NiI$_2$. (arXiv:2309.11217v1 [cond-mat.mtrl-sci])
Mohammad Amini, Adolfo O. Fumega, Héctor González-Herrero, Viliam Vaňo, Shawulienu Kezilebieke, Jose L. Lado, Peter Liljeroth

Progress in layered van der Waals materials has resulted in the discovery of ferromagnetic and ferroelectric materials down to the monolayer limit. Recently, evidence of the first purely two-dimensional multiferroic material was reported in monolayer NiI$_2$. However, probing multiferroicity with scattering-based and optical bulk techniques is challenging on 2D materials, and experiments on the atomic scale are needed to fully characterize the multiferroic order at the monolayer limit. Here, we use scanning tunneling microscopy (STM) supported by theoretical calculations based on density functional theory (DFT) to probe and characterize the multiferroic order in monolayer NiI$_2$. We demonstrate that the type-II multiferroic order displayed by NiI$_2$, arising from the combination of a magnetic spin spiral order and a strong spin-orbit coupling, allows probing the multiferroic order in the STM experiments. Moreover, we directly probe the magnetoelectric coupling of NiI$_2$ by external electric field manipulation of the multiferroic domains. Our findings establish a novel point of view to analyse magnetoelectric effects at the microscopic level, paving the way towards engineering new multiferroic orders in van der Waals materials and their heterostructures.

Variability and Reliability of Graphene Field-Effect Transistors with CaF2 Insulators. (arXiv:2309.11233v1 [])
Yury Yu. Illarionov, Theresia Knobloch, Burkay Uzlu, Alexander G. Banshikov, Iliya A. Ivanov, Viktor Sverdlov, Mikhail I. Vexler, Michael Waltl, Zhenxing Wang, Bibhas Manna, Daniel Neumaier, Max C. Lemme, Nikolai S. Sokolov, Tibor Grasser

Graphene is a promising material for applications as a channel in graphene field-effect transistors (GFETs) which may be used as a building block for optoelectronics, high-frequency devices and sensors. However, these devices require gate insulators which ideally should form atomically flat interfaces with graphene and at the same time contain small densities of traps to maintain high device stability. Previously used amorphous oxides, such as SiO2 and Al2O3, however, typically suffer from oxide dangling bonds at the interface, high surface roughness and numerous border oxide traps. In order to address these challenges, here we use for the first time 2nm thick epitaxial CaF2 as a gate insulator in GFETs. By analyzing device-to-device variability for over 200 devices fabricated in two batches, we find that tens of them show similar gate transfer characteristics. Our statistical analysis of the hysteresis up to 175C has revealed that while an ambient-sensitive counterclockwise hysteresis can be present in some devices, the dominant mechanism is thermally activated charge trapping by border defects in CaF2 which results in the conventional clockwise hysteresis. We demonstrate that both the hysteresis and bias-temperature instabilities in our GFETs with CaF2 are comparable to similar devices with SiO2 and Al2O3. In particular, we achieve a small hysteresis below 0.01 V for equivalent oxide thickness (EOT) of about 1 nm at the electric fields up to 15 MV/cm and sweep times in the kilosecond range. Thus, our results demonstrate that crystalline CaF2 is a promising insulator for highly-stable GFETs.

1D-confined crystallization routes for tungsten phosphides. (arXiv:2309.11314v1 [cond-mat.mtrl-sci])
Gangtae Jin, Christian D. Multunas, James L. Hart, Mehrdad T. Kiani, Quynh P. Sam, Han Wang, Yeryun Cheon, Khoan Duong, David J. Hynek, Hyeuk Jin Han, Ravishankar Sundararaman, Judy J. Cha

Topological materials confined in one-dimension (1D) can transform computing technologies, such as 1D topological semimetals for nanoscale interconnects and 1D topological superconductors for fault-tolerant quantum computing. As such, understanding crystallization of 1D-confined topological materials is critical. Here, we demonstrate 1D-confined crystallization routes during template-assisted nanowire synthesis where we observe diameter-dependent phase selectivity for topological metal tungsten phosphides. A phase bifurcation occurs to produce tungsten monophosphide and tungsten diphosphide at the cross-over nanowire diameter of ~ 35 nm. Four-dimensional scanning transmission electron microscopy was used to identify the two phases and to map crystallographic orientations of grains at a few nm resolution. The 1D-confined phase selectivity is attributed to the minimization of the total surface energy, which depends on the nanowire diameter and chemical potentials of precursors. Theoretical calculations were carried out to construct the diameter-dependent phase diagram, which agrees with experimental observations. Our find-ings suggest a new crystallization route to stabilize topological materials confined in 1D.

Transport-based fusion that distinguishes between Majorana and Andreev bound states. (arXiv:2309.11328v1 [cond-mat.mes-hall])
Maximilian Nitsch, Rubén Seoane Souto, Stephanie Matern, Martin Leijnse

It has proven difficult to distinguish between topological Majorana bound states and nontopological Andreev bound states and to measure the unique properties of the former. In this work, we aim to alleviate this problem by proposing and theoretically analyzing a new type of fusion protocol based on transport measurements in a Majorana box coupled to normal leads. The protocol is based on switching between different nanowire pairs being tunnel coupled to one of the leads. For a Majorana system, this leads to switching between different states associated with parity blockade. The charge being transmitted at each switch provides a measurement of the Majorana fusion rules. Importantly, the result is different for a system with nontopological Andreev bound states. The proposed protocol only requires measuring a DC current combined with fast gate-control of the tunnel couplings.

Energetics of twisted elastic filament pairs. (arXiv:2309.11344v1 [cond-mat.soft])
Julien Chopin, Animesh Biswas, Arshad Kudrolli

We investigate the elastic energy stored in a filament pair as a function of applied twist by measuring torque under prescribed end-to-end separation conditions. We show that the torque increases rapidly to a peak with applied twist when the filaments are initially separate, then decreases to a minimum as the filaments cross and come into contact. The torque then increases again while the filaments form a double helix with increasing twist. A nonlinear elasto-geometric model that combines the effect of geometrical nonlinearities with large stretching and self-twist is shown to capture the evolution of the helical geometry, the torque profile, and the stored energy with twist. We find that a large fraction of the total energy is stored in stretching the filaments, which increases with separation distance and applied tension. We find that only a small fraction of energy is stored in the form of bending energy, and that the contribution due to contact energy is negligible. Our study highlights the consequences of stretchablility on filament twisting which is a fundamental topological transformation relevant to making ropes, tying shoelaces, actuating robots, and the physical properties of entangled polymers.

Orientational dynamics in supercooled glycerol computed from MD simulations: self and cross contributions. (arXiv:2309.11369v1 [cond-mat.soft])
Marceau Hénot, Pierre-Michel Déjardin, François Ladieu

The orientational dynamics of supercooled glycerol using molecular dynamics simulations for temperatures ranging from 323 K to 253 K, is probed through correlation functions of first and second ranks of Legendre polynomials, pertaining respectively to dielectric spectroscopy (DS) and depolarized dynamic light scattering (DDLS). The self, cross, and total correlation functions are compared with relevant experimental data. The computations reveal the low sensitivity of DDLS to cross-correlations, in agreement with what is found in experimental work, and strengthen the idea of directly comparing DS and DDLS data to evaluate the effect of cross-correlations in polar liquids. The analysis of the net static cross-correlations and their spatial decomposition shows that, although cross-correlations extend over nanometric distances, their net magnitude originates, in the case of glycerol, from the first shell of neighbouring molecules. Accessing the angular dependence of the static correlation allows us to get a microscopic understanding of why the rank-1 correlation function is more sensitive to cross-correlation than its rank-2 counterpart.

Flat band superconductivity in a system with a tunable quantum metric : the stub lattice. (arXiv:2309.11440v1 [cond-mat.supr-con])
Maxime Thumin, Georges Bouzerar

Over the past years, one witnesses a growing interest in flat band (FB) physics which has become a playground for exotic phenomena. In this study, we address the FB superconductivity in onedimensional stub chain. In contrast to the sawtooth chain or the creutz ladder, for a given strength of the attractive electron-electron interaction, the stub chain allows the tuning of the real space spreading of the FB eigenstates (quantum metric or QM). We study in detail the interplay between the interaction strength and the mean value of the QM \langle g \rangle on the pairings and on the superfluid weight D_s. Our calculations reveal several interesting and intriguing features. For instance, in the weak coupling regime, D_s with respect to \langle g \rangle exhibits two different types of behaviour. Despite the fact that the pairings differs drastically, D_s scales linearly with the QM only when its \langle g \rangle is large enough (small gap limit). On the other hand, when the QM is of small amplitude an unusual power law is found, more precisely D_s \propto \langle g \rangle^\nu where \nu \longrightarrow 2 in the limit of large single particle gap. In addition to the numerical calculations, we have provided several analytical results which shed light on the physics in both the weak and strong coupling regime. Finally, we have addressed the impact of the thermal fluctuations on the superfluid weight.

Intrinsic superconducting diode effects in tilted Weyl and Dirac semimetals. (arXiv:2309.11501v1 [cond-mat.supr-con])
Kai Chen, Bishnu Karki, Pavan Hosur

We explore Weyl and Dirac semimetals with tilted nodes as platforms for realizing an intrinsic superconducting diode effect. Although tilting breaks sufficient spatial and time-reversal symmetries, we prove that -- at least for conventional $s$-wave singlet pairing -- the effect is forbidden by an emergent particle-hole symmetry at low energies if the Fermi level is tuned to the nodes. Then, as a stepping stone to the three-dimensional semimetals, we analyze a minimal one-dimensional model with a tilted helical node using Ginzburg-Landau theory. While one might naively expect a drastic enhancement of the effect when the node turns from type-I to type-II, we find that the presence of multiple Fermi pockets is more important as it enables multiple pairing amplitudes with indepedent contributions to supercurrents in opposite directions. Equipped with this insight, we construct minimal lattice models of Weyl and Dirac semimetals and study the superconducting diode effect in them. Once again, we see a substantial enhancement when the normal state has multiple Fermi pockets per node that can accommodate more than one pairing channel. In summary, this study sheds light on the key factors governing the intrinsic superconducting diode effect in systems with asymmetric band structures and paves the way for realizing it in topological semimetals.

An intrinsic nonlinear Ohmic current. (arXiv:2207.01182v3 [cond-mat.mes-hall] UPDATED)
YuanDong Wang, ZhiFan Zhang, Zhen-Gang Zhu, Gang Su

It is known that intrinsic currents in magnetic metals often appear in the direction perpendicular to the external field for linear and nonlinear responses. Distinct from three kinds of known nonlinear currents, namely, the Drude contribution, the Berry curvature dipole induced current and the Berry connection polarization induced current, here we report a intrinsic nonlinear current with breaking time-reversal symmetry. This new kind of intrinsic nonlinear current from the nontrivial Berry connection polarizability may emerge in the longitudinal or transverse direction, and both are dissipative Ohmic currents. We unveil 66 magnetic point group symmetries that can accommodate such nonlinear current, and possible candidate materials are proposed. This theory is also applied to observe the nonlinear current we proposed in one- and two-dimensional Dirac systems as examples.

Observation of terahertz second harmonic generation from Dirac surface states in the topological insulator Bi$_2$Se$_3$. (arXiv:2301.05271v2 [cond-mat.str-el] UPDATED)
Jonathan Stensberg, Xingyue Han, Zhuoliang Ni, Xiong Yao, Xiaoyu Yuan, Debarghya Mallick, Akshat Gandhi, Seongshik Oh, Liang Wu

We report the observation of second harmonic generation with high conversion efficiency $\sim 0.005\%$ in the terahertz regime from thin films of the topological insulator Bi$_2$Se$_3$ that exhibit the linear photogalvanic effect, measured via time-domain terahertz spectroscopy and terahertz emission, respectively. As neither phenomena is observable from topologically trivial In-doped Bi$_2$Se$_3$, and since no enhancement is observed when subject to band bending, the efficient thickness-independent nonliear responses are attributable to the Dirac fermions of topological surface states of Bi$_2$Se$_3$. This observation of intrinsic terahertz second harmonic generation in an equilibrium system unlocks the full suite of both even and odd harmonic orders in the terahertz regime and opens new pathways to probing quantum geometry via intraband nonlinear processes.

Lightwave-controlled band engineering in quantum materials. (arXiv:2303.13044v2 [cond-mat.mes-hall] UPDATED)
Sambit Mitra, Álvaro Jiménez-Galán, Marcel Neuhaus, Rui E F Silva, Volodymyr Pervak, Matthias F Kling, Shubhadeep Biswas

Stacking and twisting atom-thin sheets create superlattice structures with unique emergent properties, while tailored light fields can manipulate coherent electron transport on ultrafast timescales. The unification of these two approaches may lead to ultrafast creation and manipulation of band structure properties, which is a crucial objective for the advancement of quantum technology. Here, we address this by demonstrating a tailored lightwave-driven analogue to twisted layer stacking. This results in sub-femtosecond control of time-reversal symmetry breaking and thereby band structure engineering in a hexagonal boron nitride monolayer. The results practically demonstrate the realization of the topological Haldane model in an insulator. Twisting the lightwave relative to the lattice orientation enables switching between band configurations, providing unprecedented control over the magnitude and location of the band gap, and curvature. A resultant asymmetric population at complementary quantum valleys lead to a measurable valley Hall current, detected via optical harmonic polarimetry. The universality and robustness of the demonstrated sub-femtosecond control opens a new way to band structure engineering on the fly paving a way towards large-scale ultrafast quantum devices for real-world applications.

The quantum skyrmion Hall effect in f electron systems. (arXiv:2304.08006v2 [cond-mat.str-el] UPDATED)
Robert Peters, Jannis Neuhaus-Steinmetz, Thore Posske

The flow of electric current through a two-dimensional material in a magnetic field gives rise to the family of Hall effects. The quantum versions of these effects accommodate robust electronic edge channels and fractional charges. Recently, the Hall effect of skyrmions, classical magnetic quasiparticles with a quantized topological charge, has been theoretically and experimentally reported, igniting ideas on a quantum version of this effect. To this end, we perform dynamical mean field theory calculations on localized $f$ electrons coupled to itinerant $c$ electrons in the presence of spin-orbit interaction and a magnetic field. Our calculations reveal localized nano quantum skyrmions that start moving transversally when a charge current in the itinerant electrons is applied. The results show the time-transient build-up of the quantum skyrmion Hall effect, accompanied by an Edelstein effect and a magnetoelectric effect that rotate the spins. This work motivates studies about the steady state of the quantum skyrmion Hall effect, looking for eventual quantum skyrmion edge channels and their transport properties.

Multiple types of unconventional quasiparticles in the chiral crystal CsBe$_2$F$_5$. (arXiv:2305.06930v4 [cond-mat.mtrl-sci] UPDATED)
Xin-Yue Kang, Jin-Yang Li, Si Li

Unconventional topological quasiparticles have recently garnered significant attention in the realm of condensed matter physics. Here, based on first-principles calculations and symmetry analysis, we reveal the coexistence of multiple types of interesting unconventional topological quasiparticles in the phonon spectrum of the chiral crystal CsBe$_2$F$_5$. Specifically, we identified eight entangled phonon bands in CsBe$_2$F$_5$, which give rise to various unconventional topological quasiparticles, including the spin-1 Weyl point, the charge-2 Dirac point, the nodal surface, and the hourglass nodal loop. We demonstrate that these unconventional topological quasiparticles are protected by crystal symmetry. We show that there are two large Fermi arcs connecting projections of the bulk spin-1 Weyl point and charge-2 Dirac point on the (001) surface and across the entire surface Brillouin zone. Our work not only elucidates the intriguing topological properties of chiral crystals but also provides an excellent material platform for exploring the fascinating physics associated with multiple types of unconventional topological quasiparticles.

Casimir-Lifshitz force between graphene-based structures out of thermal equilibrium. (arXiv:2305.18946v3 [cond-mat.mes-hall] UPDATED)
Youssef Jeyar, Kevin Austry, Minggang Luo, Brahim Guizal, H. B. Chan, Mauro Antezza

We study the non equilibrium Casimir-Lifshitz force between graphene-based parallel structures held at different temperatures and in presence of an external thermal bath at a third temperature. The graphene conductivity, which is itself a function of temperature, as well as of chemical potential, allows us to tune in situ the Casimir-Lifshitz force. We explore different non equilibrium configurations while considering different values of the graphene chemical potential. Particularly interesting cases are investigated, where the force can change sign going from attractive to repulsive or where the force becomes non monotonic with respect to chemical potential variations, contrary to the behaviour under thermal equilibrium.

Solitons induced by an in-plane magnetic field in rhombohedral multilayer graphene. (arXiv:2306.05237v2 [cond-mat.mes-hall] UPDATED)
Max Tymczyszyn, Peter H. Cross, Edward McCann

We model the influence of an in-plane magnetic field on the orbital motion of electrons in rhombohedral graphene multilayers. For zero field, the low-energy band structure includes a pair of flat bands near zero energy which are localized on the surface layers of a finite thin film. For finite field, we find that the zero-energy bands persist and that level bifurcations occur at energies determined by the component of the in-plane wave vector $q$ that is parallel to the external field. The occurrence of level bifurcations is explained by invoking semiclassical quantization of the zero field Fermi surface of rhombohedral graphite. We find parameter regions with a single isoenergetic contour of Berry phase zero corresponding to a conventional Landau level spectrum and regions with two isoenergetic contours, each of Berry phase $\pi$, corresponding to a Dirac-like spectrum of levels. We write down an analogous one-dimensional tight-binding model and relate the persistence of the zero-energy bands in large magnetic fields to a soliton texture supporting zero-energy states in the Su-Schreiffer-Heeger model. We show that different states contributing to the zero-energy flat bands in rhombohedral graphene multilayers in a large field, as determined by the wave vector $q$, are localized on different bulk layers of the system, not just the surfaces.

Relaxation effects in twisted bilayer molybdenum disulfide: structure, stability, and electronic properties. (arXiv:2306.07130v2 [cond-mat.mtrl-sci] UPDATED)
Florian M. Arnold, Alireza Ghasemifard, Agnieszka Kuc, Jens Kunstmann, Thomas Heine

Manipulating the interlayer twist angle is a powerful tool to tailor the properties of layered two-dimensional crystals. The twist angle has a determinant impact on these systems' atomistic structure and electronic properties. This includes the corrugation of individual layers, formation of stacking domains and other structural elements, and electronic structure changes due to the atomic reconstruction and superlattice effects. However, how these properties change with the twist angle (ta) is not yet well understood. Here, we monitor the change of twisted bilayer MoS2 characteristics as function of ta. We identify distinct structural regimes, with particular structural and electronic properties. We employ a hierarchical approach ranging from a reactive force field through the density-functional-based tight-binding approach and density-functional theory. To obtain a comprehensive overview, we analyzed a large number of twisted bilayers with twist angles in the range 0.2-59.6deg. Some systems include up to half a million atoms, making structure optimization and electronic property calculation challenging. For 13<ta<47, the structure is well-described by a moir\'e regime composed of two rigidly twisted monolayers. At small ta (ta<3 and 57<ta), a domain-soliton regime evolves, where the structure contains large triangular stacking domains, separated by a network of strain solitons and short-ranged high-energy nodes. The corrugation of the layers and the emerging superlattice of solitons and stacking domains affects the electronic structure. Emerging predominant characteristic features are Dirac cones at K and kagome bands. These features flatten for ta approaching 0 and 60deg. Our results show at which ta range the characteristic features of the reconstruction emerge and give rise to exciting electronics. We expect our findings also to be relevant for other twisted bilayer systems.

Topological electronic bands in crystalline solids. (arXiv:2307.16258v2 [cond-mat.str-el] UPDATED)
Andrew T. Boothroyd

Topology is now securely established as a means to explore and classify electronic states in crystalline solids. This review provides a gentle but firm introduction to topological electronic band structure suitable for new researchers in the field. I begin by outlining the relevant concepts from topology, then give a summary of the theory of non-interacting electrons in periodic potentials. Next, I explain the concepts of the Berry phase and Berry curvature, and derive key formulae. The remainder of the article deals with how these ideas are applied to classify crystalline solids according to the topology of the electronic states, and the implications for observable properties. Among the topics covered are the role of symmetry in determining band degeneracies in momentum space, the Chern number and Z2 topological invariants, surface electronic states, two- and three-dimensional topological insulators, and Weyl and Dirac semimetals

Andreev reflection of quantum Hall states through a quantum point contact. (arXiv:2309.01856v2 [cond-mat.mes-hall] UPDATED)
Mehdi Hatefipour, Joseph J. Cuozzo, Ido Levy, William M. Strickland, Dylan Langone, Enrico Rossi, Javad Shabani

We investigate the interplay between the quantum Hall (QH) effect and superconductivity in InAs surface quantum well (SQW)/NbTiN heterostructures using a quantum point contact (QPC). We use QPC to control the proximity of the edge states to the superconductor. By measuring the upstream and downstream resistances of the device, we investigate the efficiency of Andreev conversion at the InAs/NbTiN interface. Our experimental data is analyzed using the Landauer-Buttiker formalism, generalized to allow for Andreev reflection processes. We show that by varying the voltage of the QPC, $V_{QPC}$, the average Andreev reflection, $A$, at the QH-SC interface can be tuned from 50% to 10%. The evolution of $A$ with $V_{QPC}$ extracted from the measurements exhibits plateaus separated by regions for which $A$ varies continuously with $V_{QPC}$. The presence of plateaus suggests that for some ranges of $V_{QPC}$ the QPC might be pinching off almost completely from the QH-SC interface some of the edge modes. Our work shows a new experimental setup to control and advance the understanding of the complex interplay between superconductivity and QH effect in two-dimensional electron gas systems.

Inferring effective couplings with Restricted Boltzmann Machines. (arXiv:2309.02292v2 [cond-mat.dis-nn] UPDATED)
Aurélien Decelle, Cyril Furtlehner, Alfonso De Jesus Navas Gómez, Beatriz Seoane

Generative models offer a direct way to model complex data. Among them, energy-based models provide us with a neural network model that aims to accurately reproduce all statistical correlations observed in the data at the level of the Boltzmann weight of the model. However, one challenge is to understand the physical interpretation of such models. In this study, we propose a simple solution by implementing a direct mapping between the energy function of the Restricted Boltzmann Machine and an effective Ising spin Hamiltonian that includes high-order interactions between spins. This mapping includes interactions of all possible orders, going beyond the conventional pairwise interactions typically considered in the inverse Ising approach, and allowing the description of complex datasets. Earlier works attempted to achieve this goal, but the proposed mappings did not do properly treat the complexity of the problem or did not contain direct prescriptions for practical application. To validate our method, we performed several controlled numerical experiments where we trained the RBMs using equilibrium samples of predefined models containing local external fields, two-body and three-body interactions in various low-dimensional topologies. The results demonstrate the effectiveness of our proposed approach in learning the correct interaction network and pave the way for its application in modeling interesting datasets. We also evaluate the quality of the inferred model based on different training methods.

Unconventional superconducting pairing in a B20 Kramers Weyl semimetal. (arXiv:2309.05880v2 [cond-mat.supr-con] UPDATED)
Sougata Mardanya, Mehdi Kargarian, Rahul Verma, Tay-Rong Chang, Sugata Chowdhury, Hsin Lin, Arun Bansil, Amit Agarwal, Bahadur Singh

Topological superconductors present an ideal platform for exploring nontrivial superconductivity and realizing Majorana boundary modes in materials. However, finding a single-phase topological material with nontrivial superconducting states is a challenge. Here, we predict nontrivial superconductivity in the pristine chiral metal RhGe with a transition temperature of 5.8 K. Chiral symmetries in RhGe enforce multifold Weyl fermions at high-symmetry momentum points and spin-polarized Fermi arc states that span the whole surface Brillouin zone. These bulk and surface chiral states support multiple type-II van Hove singularities that enhance superconductivity in RhGe. Our detailed analysis of superconducting pairing symmetries involving Chiral Fermi pockets in RhGe, indicates the presence of nontrivial superconducting pairing. Our study establishes RhGe as a promising candidate material for hosting mixed-parity pairing and topological superconductivity.

Found 7 papers in prb
Date of feed: Thu, 21 Sep 2023 03:17:15 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)

Chiral spin channels in curved graphene $pn$ junctions
Dario Bercioux, Diego Frustaglia, and Alessandro De Martino
Author(s): Dario Bercioux, Diego Frustaglia, and Alessandro De Martino

We show that the chiral modes in circular graphene $pn$ junctions provide an advantage for spin manipulation via spin-orbit coupling compared to semiconductor platforms. We derive the effective Hamiltonian for the spin dynamics of the junction's zero modes and calculate their quantum phases. We find…

[Phys. Rev. B 108, 115140] Published Wed Sep 20, 2023

Thermopower of the dice lattice
Han-Lin Liu, L. Hao, J. Wang, and Jun-Feng Liu
Author(s): Han-Lin Liu, L. Hao, J. Wang, and Jun-Feng Liu

The Dice lattice structure is similar to the graphene honeycomb lattice, but with an imbalance atom in each hexagon center giving rise to a dispersionless flat band, which intersects the pseudopsin $S=1$ Dirac bands through the Dirac point. In this work, we report a theoretical study on the thermopo…

[Phys. Rev. B 108, 115141] Published Wed Sep 20, 2023

Impact of competing energy scales on the shell-filling sequence in elliptic bilayer graphene quantum dots
S. Möller, L. Banszerus, A. Knothe, L. Valerius, K. Hecker, E. Icking, K. Watanabe, T. Taniguchi, C. Volk, and C. Stampfer
Author(s): S. Möller, L. Banszerus, A. Knothe, L. Valerius, K. Hecker, E. Icking, K. Watanabe, T. Taniguchi, C. Volk, and C. Stampfer

We report on a detailed investigation of the shell-filling sequence in electrostatically defined elliptic bilayer graphene quantum dots (QDs) in the regime of low charge carrier occupation, $N≤12$, by means of magnetotransport spectroscopy and numerical calculations. We show the necessity of includi…

[Phys. Rev. B 108, 125128] Published Wed Sep 20, 2023

Nearly flat Chern band in periodically strained monolayer and bilayer graphene
Xiaohan Wan, Siddhartha Sarkar, Kai Sun, and Shi-Zeng Lin
Author(s): Xiaohan Wan, Siddhartha Sarkar, Kai Sun, and Shi-Zeng Lin

The flat band is a key ingredient for the realization of interesting quantum states for functionalities. In this paper, we investigate the conditions for the flat band in both monolayer and bilayer graphene under periodic strain. We find topological nearly flat bands with homogeneous distribution of…

[Phys. Rev. B 108, 125129] Published Wed Sep 20, 2023

Higher-order topological superconductors characterized by Fermi level crossings
Hong Wang and Xiaoyu Zhu
Author(s): Hong Wang and Xiaoyu Zhu

We demonstrate that level crossings at the Fermi energy serve as robust indicators for higher-order topology in two-dimensional superconductors of symmetry class D. These crossings occur when the boundary condition in one direction is continuously varied from periodic to open, revealing the topologi…

[Phys. Rev. B 108, 125426] Published Wed Sep 20, 2023

Quasicrystalline Weyl points and dense Fermi-Bragg arcs
André Grossi e Fonseca, Thomas Christensen, John D. Joannopoulos, and Marin Soljačić
Author(s): André Grossi e Fonseca, Thomas Christensen, John D. Joannopoulos, and Marin Soljačić

We introduce a general mechanism for obtaining Weyl points in a stack of two-dimensional (2D) quasicrystals, which can be extended to any stack of aperiodic layers. We do so by driving a topological phase transition with the vertical crystal momentum as the tuning parameter, which leads to gap closu…

[Phys. Rev. B 108, L121109] Published Wed Sep 20, 2023

Electronic structure of the putative room-temperature superconductor ${\text{Pb}}_{9}\text{Cu}{({\text{PO}}_{4})}_{6}\text{O}$
Liang Si and Karsten Held
Author(s): Liang Si and Karsten Held

A recent paper [Lee et al., J. Kor. Cryst. Growth Cryst. Technol. 33, 61 (2023)] provides some experimental indications that ${\mathrm{Pb}}_{10−x}{\mathrm{Cu}}_{x}{({\mathrm{PO}}_{4})}_{6}\mathrm{O}$ with $x≈1$, coined LK-99, might be a room-temperature superconductor at ambient pressure. Our densi…

[Phys. Rev. B 108, L121110] Published Wed Sep 20, 2023

Found 1 papers in prl
Date of feed: Thu, 21 Sep 2023 03:17:15 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)

When Quantum Fluctuations Meet Structural Instabilities: The Isotope- and Pressure-Induced Phase Transition in the Quantum Paraelectric NaOH
Sofiane Schaack, Etienne Mangaud, Erika Fallacara, Simon Huppert, Philippe Depondt, and Fabio Finocchi
Author(s): Sofiane Schaack, Etienne Mangaud, Erika Fallacara, Simon Huppert, Philippe Depondt, and Fabio Finocchi

Anhydrous sodium hydroxide, a common and structurally simple compound, shows spectacular isotope effects: NaOD undergoes a first-order transition, which is absent in NaOH. By combining ab initio electronic structure calculations with Feynman path integrals, we show that NaOH is an unusual example of…

[Phys. Rev. Lett. 131, 126101] Published Wed Sep 20, 2023

Found 1 papers in pr_res
Date of feed: Thu, 21 Sep 2023 03:17:13 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)

Evading noise in multiparameter quantum metrology with indefinite causal order
Aaron Z. Goldberg, Khabat Heshami, and L. L. Sánchez-Soto
Author(s): Aaron Z. Goldberg, Khabat Heshami, and L. L. Sánchez-Soto

Quantum theory allows the traversing of multiple channels in a superposition of different orders. When the order in which the channels are traversed is controlled by an auxiliary quantum system, various unknown parameters of the channels can be estimated by measuring only the control system, even wh…

[Phys. Rev. Research 5, 033198] Published Wed Sep 20, 2023

Found 2 papers in nano-lett
Date of feed: Wed, 20 Sep 2023 13:14:21 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] Pressure-Induced Dynamic Tuning of Interlayer Coupling in Twisted WSe2/WSe2 Homobilayers
Xing Xie, Junnan Ding, Biao Wu, Haihong Zheng, Shaofei Li, Chang-Tian Wang, Jun He, Zongwen Liu, Jian-Tao Wang, and Yanping Liu

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.3c01640

[ASAP] Two-Dimensional Silver-Chalcogenolate-Based Cluster-Assembled Material: A p-type Semiconductor
Anish Kumar Das, Sourav Biswas, Arijit Kayal, Arthur C. Reber, Subhrajyoti Bhandary, Deepak Chopra, Joy Mitra, Shiv N. Khanna, and Sukhendu Mandal

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.3c02269

Found 1 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)

Revealing inverted chirality of hidden domain wall states in multiband systems without topological transition
Sangmo Cheon

Communications Physics, Published online: 20 September 2023; doi:10.1038/s42005-023-01367-x

Chirality plays a key role in non-trivial topological systems and can be used to engineer a range of exotic physical phenomena. Here, the authors investigate hidden chiral domain wall states and their topological properties in a double-chain Su-Schrieffer-Heeger model and elucidate a series of single and double gap phases that occur by varying the dimerization and interchain coupling.