Found 40 papers in cond-mat
Date of feed: Wed, 19 Jul 2023 00:30:00 GMT

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Twice Hidden String Order and Competing Phases in the Spin-1/2 Kitaev-Gamma Ladder. (arXiv:2307.08731v1 [cond-mat.str-el])
Erik S. Sørensen, Hae-Young Kee

While a complete understanding of the phase-diagram of Kitaev materials has yet to be achieved, important insights can be gained from studying low-dimensional models such as chains and ladders. Here we focus on the Kitaev-Gamma ladder with both Kitaev ($K$) and Gamma ($\Gamma$) couplings. We first report two new phases near $K$=0, $\Gamma\mathord{>}$0, termed SPT$_\alpha$, and SPT$_\beta$, which are magnetically disordered and characterize them as symmetry protected topological (SPT) states. We then clarify the nature of the A$\Gamma$-phase surrounding the point $K$=0, $\Gamma\mathord{=}1$ point, by revealing a non-zero string order parameter. The string order is uncovered by first applying a local unitary transformation, then a non-local, arriving at a model which shows ordinary long-range order. In a sense, the order is therefore twice hidden. In addition to the long-range string order, the existence of degenerate edge modes is another hallmark of a SPT phase, of which there are four in the A$\Gamma$-phase. Remarkably, the edge-states in the A$\Gamma$-phase only respond to a field applied along the $\mathbf{\hat{b}}$-direction ([1-10]), contrary to the Kitaev phases in the ladder. Furthermore, the topology of the A$\Gamma$-phase is robust under a field applied in the $\mathbf{\hat{a}}$ and $\mathbf{\hat{c}}$ directions, as the degeneracy in the entanglement spectrum is intact. The A$\Gamma$-phase is then protected by $TR\times \mathcal{R}_{b}$ symmetry, the product of time-reversal ($TR$) and $\pi$ rotation around the $\mathbf{\hat b}$-axis ($\mathcal{R}_{b}$).

Disordered $\mathcal{N} = (2, 2)$ Supersymmetric Field Theories. (arXiv:2307.08742v1 [hep-th])
Chi-Ming Chang, Xiaoyang Shen

We investigate a large class of $\mathcal{N} = (2, 2)$ supersymmetric field theories in two dimensions, which contains the Murugan-Stanford-Witten model, and can be naturally regarded as a disordered generalization of the two-dimensional Landau-Ginzburg models. We analyze the two and four-point functions of chiral superfields, and extract from them the central charge, the operator spectrum, and the chaos exponent in these models. Some of the models exhibit a conformal manifold parameterized by the variances of the random couplings. We compute the Zamolodchikov metrics on the conformal manifold, and demonstrate that the chaos exponent varies nontrivally along the conformal manifolds. Finally, we introduce and perform some preliminary analysis of a disordered generalization of the gauged linear sigma models, and discuss the low energy theories as ensemble averages of Calabi-Yau sigma models over complex structure moduli space.

Unconventional superfluidity and quantum geometry of topological bosons. (arXiv:2307.08748v1 [cond-mat.quant-gas])
Ilya Lukin, Andrii Sotnikov, Alexander Kruchkov

We investigate superfluidity of bosons in gapped topological bands and discover a new phase that has no counterparts in the previous literature. This phase is characterized by a highly unconventional modulation of the order parameter, breaking the crystallographic symmetry, and for which the condensation momentum is neither zero nor any other high-symmetry vector of the Brillouin zone. This unconventional structure impacts the spectrum of Bogoliubov excitations and, consequently, the speed of sound in the system. Even in the case of perfectly flat bands, the speed of sound and Bogoliubov excitations remain nonvanishing, provided that the underlying topology and quantum geometry are nontrivial. Furthermore, we derive detailed expressions for the superfluid weight using the Popov hydrodynamic formalism for superfluidity and provide estimates for the Berezinskii-Kosterlitz-Thouless temperature, which is significantly enhanced by the nontriviality of the underlying quantum metric. These results are applicable to generic topological bosonic bands, with or without dispersion. To illustrate our findings, we employ the Haldane model with a tunable bandwidth, including the narrow lowest-band case. Within this model, we also observe a re-entrant superfluid behavior: As the Haldane's magnetic flux is varied, the Berezinskii-Kosterlitz-Thouless transition temperature initially decreases to almost zero, only to resurface with renewed vigor.

Topological properties of a non-Hermitian quasi-one-dimensional chain with a flat band. (arXiv:2307.08754v1 [cond-mat.mes-hall])
C.Martínez-Strasser, M.A.J.Herrera, G.Palumbo, F.K.Kunst, D.Bercioux

We investigate the spectral properties of a non-Hermitian quasi-one-dimensional lattice in two possible dimerization configurations. Specifically, we focus on a non-Hermitian diamond chain that presents a zero-energy flat band. The flat band originates from wave interference and results in eigenstates with a finite contribution only on two sites of the unit cell. To achieve the non-Hermitian characteristics, we introduce non-reciprocal intrasite hopping terms in the chain. This leads to the accumulation of eigenstates on the boundary of the system, known as the non-Hermitian skin effect. Despite this accumulation of eigenstates, for one of the two possible configurations, we can characterize the presence of non-trivial edge states at zero energy by a real-space topological invariant known as the biorthogonal polarization. We show that this invariant, evaluated using the destructive interference method, characterizes the non-trivial phase of the non-Hermitian diamond chain. For the other possible non-Hermitian configuration, we find that there is a finite quantum metric associated with the flat band. Additionally, we observe the skin effect despite having the system a purely real or imaginary spectrum. For both configurations, we show that two non- Hermitian diamond chains can be mapped into two models of the Su-Schrieffer-Heeger chains, either non-Hermitian and Hermitian, in the presence of a flat band. This mapping allows us to draw valuable insights into the behavior and properties of these systems.

Decoding chirality in circuit topology of a self entangled chain through braiding. (arXiv:2307.08805v1 [cond-mat.soft])
Jonas Berx, Alireza Mashaghi

Circuit topology employs fundamental units of entanglement, known as soft contacts, for constructing knots from the bottom up, utilising circuit topology relations, namely parallel, series, cross, and concerted relations. In this article, we further develop this approach to facilitate the analysis of chirality, which is a significant quantity in polymer chemistry. To achieve this, we translate the circuit topology approach to knot engineering into a braid-theoretic framework. This enables us to calculate the Jones polynomial for all possible binary combinations of contacts in cross or concerted relations and to show that, for series and parallel relations, the polynomial factorises. Our results demonstrate that the Jones polynomial provides a powerful tool for analysing the chirality of molecular knots constructed using circuit topology. The framework presented here can be used to design and engineer a wide range of entangled chain with desired chiral properties, with potential applications in fields such as materials science and nanotechnology.

Superfluid phase transition of nanoscale-confined helium-3. (arXiv:2307.08808v1 [cond-mat.supr-con])
Canon Sun, Adil Attar, Igor Boettcher

We theoretically investigate the superfluid phase transition of helium-3 under nanoscale confinement of one spatial dimension realized in recent experiments. Instead of the 3x3 complex matrix order parameter found in the three-dimensional system, the quasi two-dimensional superfluid is described by a reduced 3x2 complex matrix. It features a nodal quasiparticle spectrum, regardless of the value of the order parameter. The origin of the 3x2 order parameter is first illustrated via the two-particle Cooper problem, where Cooper pairs in the $p_x$ and $p_y$ orbitals are shown to have a lower bound state energy than those in $p_z$ orbitals, hinting at their energetically favorable role at the phase transition. We then compute the Landau free energy under confinement within the mean-field approximation and show that the critical temperature for condensation of the 3x2 order parameter is larger than for other competing phases. Through exact minimization of the mean-field free energy, we show that mean-field theory predicts precisely two energetically degenerate superfluid orders to emerge at the transition that are not related by symmetry: the A-phase and the planar phase. Beyond the mean-field approximation, we show that strong-coupling corrections favor the A-phase observed in experiment, whereas weak-coupling perturbative renormalization group predicts the planar phase to be stable.

MBE growth of axion insulator candidate EuIn2As2. (arXiv:2307.08831v1 [cond-mat.mtrl-sci])
Muhsin Abdul Karim, Jiashu Wang, David Graf, Kota Yoshimura, Sara Bey, Tatyana Orlova, Maksym Zhukovskyi, Xinyu Liu, Badih A. Assaf

The synthesis of thin films of magnetic topological materials is necessary to achieve novel quantized Hall effects and electrodynamic responses. EuIn2As2 is a recently predicted topological axion insulator that has an antiferromagnetic ground state and an inverted band structure but that has only been synthesized and studied as a single crystal. We report on the synthesis of c-axis oriented EuIn2As2 films by molecular beam epitaxy on sapphire substrates. By careful tuning of the substrate temperature during growth, we stabilize the Zintl phase of EuIn2As2 expected to be topologically non-trivial. The magnetic properties of these films reproduce those seen in single crystals but their resistivity is enhanced when grown at lower temperatures. We additionally find that the magnetoresistance of EuIn2As2 is negative even up to fields as high as 31T but while it is highly anisotropic at low fields, it becomes nearly isotropic at high magnetic fields above 5T. Overall, the transport characteristics of EuIn2As2 appear similar to those of chalcogenide topological insulators, motivating the development of devices to gate tune the Fermi energy to reveal topological features in quantum transport.

X-ray Spectroscopy of a Rare-Earth Molecular System Measured at the Single Atom Limit in Room Temperature. (arXiv:2307.08862v1 [cond-mat.mtrl-sci])
Sarah Wieghold, Nozomi Shirato, Xinyue Cheng, Kyaw Zin Latt, Daniel Trainer, Richard Sottie, Daniel Rosenmann, Eric Masson, Volker Rose, Saw Wai Hla

We investigate the limit of X-ray detection at room temperature on rare-earth molecular films using lanthanum and a pyridine-based dicarboxamide organic linker as a model system. Synchrotron X-ray scanning tunneling microscopy is used to probe the molecules with different coverages on a HOPG substrate. X-ray-induced photocurrent intensities are measured as a function of molecular coverage on the sample allowing a correlation of the amount of La ions with the photocurrent signal strength. X-ray absorption spectroscopy shows cogent M4,5 absorption edges of the lanthanum ion originated by the transitions from the 3d3/2 and 3d5/2 to 4f orbitals. X-ray absorption spectra measured in the tunneling regime further reveal an X-ray excited tunneling current produced at the M4,5 absorption edge of La ion down to the ultimate atomic limit at room temperature.

Elastic chiral Landau level and snake states in origami metamaterials. (arXiv:2307.08887v1 [cond-mat.soft])
Shuaifeng Li, Panayotis G.Kevrekidis, Jinkyu Yang

In this study, we present a method for generating a synthetic gauge field in origami metamaterials with continuously varying geometrical parameters. By modulating the mass term in the Dirac equation linearly, we create a synthetic gauge field in the vertical direction, which allows for the quantization of Landau levels through the generated pseudomagnetic field. Furthermore, we demonstrate the existence and robustness of the chiral zeroth Landau level. The unique elastic snake state is realized using the coupling between the zeroth and the first Landau levels. Our results, supported by theory and simulations, establish a feasible framework for generating pseudomagnetic fields in origami metamaterials with potential applications in waveguides and cloaking.

Observation of giant nonreciprocal charge transport from quantum Hall edge states of single surface in topological insulator. (arXiv:2307.08917v1 [cond-mat.mes-hall])
Chunfeng Li, Shuai Zhang, Zhe Ying, Boyuan Wei, Zheng Dai, Fengyi Guo, Rui Wang, Wei Chen, Xuefeng Wang, Fengqi Song

Symmetry breaking in quantum materials is of great importance and leads to novel nonreciprocal charge transport. The topological insulator system provides a unique platform to study nonreciprocal charge transport due to the exotic surface state. But it is typically small in magnitude because the contributions from the top and bottom surface of topological insulator are usually opposite. Here, we report the observation of giant nonreciprocal charge transport mediated by the quantum Hall state in intrinsic topological insulator Sn-Bi1.1Sb0.9Te2S devices, which is attributed to the coexistence of quantum Hall states and Dirac surface states. A giant nonreciprocal coefficient of up to 2.26*10^5 A^-1 is found, because only a single surface of topological insulator contributes to the nonreciprocal charge transport. Our work not only reveals the intrinsic properties of nonreciprocal charge transport in topological insulators, but also paves the way for future electronic devices.

The transport properties of Kekul\'e-ordered graphene $p$-$n$ junctions. (arXiv:2307.08932v1 [cond-mat.mes-hall])
Peipei Zhang, Chao Wang, Yu-Xian Li, Lixue Zhai, Juntao Song

The transport properties of electrons in graphene $p$-$n$ junction with uniform Kekul\'e lattice distortion have been studied using the tight-binding model and the Landauer-B\"uttiker formalism combined with the nonequilibrium Green's function method. In the Kekul\'e-ordered graphene, the original $K$ and $K^{\prime}$ valleys of the pristine graphene are folded together due to the $\sqrt{3} \times \sqrt{3}$ enlargement of the primitive cell. When the valley coupling breaks the chiral symmetry, special transport properties of Dirac electrons exist in the Kekul\'e lattice. In the O-shaped Kekul\'e graphene $p$-$n$ junction, Klein tunneling is suppressed, and only resonance tunneling occurs. In the Y-shaped Kekul\'e graphene $p$-$n$ junction, the transport of electrons is dominated by Klein tunneling. When the on-site energy modification is introduced into the Y-shaped Kekul\'e structure, both Klein tunneling and resonance tunneling occur, and the electron tunneling is enhanced. In the presence of a strong magnetic field, the conductance of O-shaped and on-site energy-modified Y-shaped Kekul\'e graphene $p$-$n$ junctions is non-zero due to the occurrence of resonance tunneling. It is also found that the disorder can enhance conductance, with conductance plateaus forming in the appropriate range of disorder strength. The ideal plateau value is found only in the Kekul\'e-Y system.

Oxidation kinetics and non-Marcusian charge transfer in dimensionally confined semiconductors. (arXiv:2307.08957v1 [cond-mat.mtrl-sci])
Ning Xu, Li Shi, Xudong Pei, Weiyang Zhang, Jian Chen, Zheng Han, Paolo Samorì, Jinlan Wang, Peng Wang, Yi Shi, Songlin Li

Electrochemical reactions represent essential processes in fundamental chemistry that foster a wide range of applications. Although most electrochemical reactions in bulk substances can be well described by the classical Marcus-Gerischer charge transfer theory, the realistic reaction character and mechanism in dimensionally confined systems remain unknown. Here, we report the multiparametric survey on the kinetics of lateral photooxidation in structurally identical WS2 and MoS2 monolayers, where electrochemical oxidation occurs at the atomically thin monolayer edges. The oxidation rate is correlated quantitatively with various crystallographic and environmental parameters, including the density of reactive sites, humidity, temperature, and illumination fluence. In particular, we observe distinctive reaction barriers of 1.4 and 0.9 eV for the two structurally identical semiconductors and uncover an unusual non-Marcusian charge transfer mechanism in these dimensionally confined monolayers due to the limit in reactant supplies. A scenario of band bending is proposed to explain the discrepancy in reaction barriers. These results add important knowledge into the fundamental electrochemical reaction theory in low-dimensional systems.

The non-Landauer Bound for the Dissipation of Bit Writing Operation. (arXiv:2307.08993v1 [cond-mat.stat-mech])
Léopold Van Brandt, Jean-Charles Delvenne

We propose a novel bound on the mimimum dissipation required in any circumstances to transfer a certain amount of charge through any resistive device. We illustrate it on the task of writing a logical 1 (encoded as a prescribed voltage) into a capacitance, through various linear or nonlinear devices. We show that, even though the celebrated Landauer bound (which only applies to bit erasure) does not apply here, one can still formulate a "non- Landauer" lower bound on dissipation, that crucially depends on the time budget to perform the operation, as well as the average conductance of the driving device. We compare our bound with empirical results reported in the literature and realistic simulations of CMOS pass and transmission gates in decananometer technology. Our non-Landauer bound turns out to be a quantitative benchmark to assess the (non-)optimality of a writing operation.

Large scale synthesis of 2D graphene oxide by mechanical milling of 3D carbon nanoparticles in air. (arXiv:2307.09011v1 [cond-mat.mtrl-sci])
Sandip Das, Subhamay Pramanik, Sumit Mukherjee, Tatan Ghosh, Rajib Nath, Probodh K. Kuiri

Graphene oxide (GO) is one of the important functional materials. Large-scale synthesis of it is very challenging. Following a simple cost-effective route, large-scale GO was produced by mechanical (ball) milling, in air, of carbon nanoparticles (CNPs) present in carbon soot in the present study. The thickness of the GO layer was seen to decrease with an increase in milling time. Ball milling provided the required energy to acquire the in-plane graphitic order in the CNPs reducing the disorders in it. As the surface area of the layered structure became more and more with the increase in milling time, more and more oxygen of air got attached to the carbon in graphene leading to the formation of GO. An increase in the time of the ball mill up to 5 hours leads to a significant increase in the content of GO. Thus ball milling can be useful to produce large-scale two-dimensional GO for a short time.

qecGPT: decoding Quantum Error-correcting Codes with Generative Pre-trained Transformers. (arXiv:2307.09025v1 [quant-ph])
Hanyan Cao, Feng Pan, Yijia Wang, Pan Zhang

We propose a general framework for decoding quantum error-correcting codes with generative modeling. The model utilizes autoregressive neural networks, specifically Transformers, to learn the joint probability of logical operators and syndromes. This training is in an unsupervised way, without the need for labeled training data, and is thus referred to as pre-training. After the pre-training, the model can efficiently compute the likelihood of logical operators for any given syndrome, using maximum likelihood decoding. It can directly generate the most-likely logical operators with computational complexity $\mathcal O(2k)$ in the number of logical qubits $k$, which is significantly better than the conventional maximum likelihood decoding algorithms that require $\mathcal O(4^k)$ computation. Based on the pre-trained model, we further propose refinement to achieve more accurately the likelihood of logical operators for a given syndrome by directly sampling the stabilizer operators. We perform numerical experiments on stabilizer codes with small code distances, using both depolarizing error models and error models with correlated noise. The results show that our approach provides significantly better decoding accuracy than the minimum weight perfect matching and belief-propagation-based algorithms. Our framework is general and can be applied to any error model and quantum codes with different topologies such as surface codes and quantum LDPC codes. Furthermore, it leverages the parallelization capabilities of GPUs, enabling simultaneous decoding of a large number of syndromes. Our approach sheds light on the efficient and accurate decoding of quantum error-correcting codes using generative artificial intelligence and modern computational power.

Defects, band bending and ionization rings in MoS2. (arXiv:2307.09046v1 [cond-mat.mtrl-sci])
Iolanda Di Bernardo, James Blyth, Liam Watson, Kaijian Xing, Yi-Hsun Chen, Shao-Yu Chen, Mark T. Edmonds, Michael S. Fuhrer

Chalcogen vacancies in transition metal dichalcogenides are widely acknowledged as both donor dopants and as a source of disorder. The electronic structure of sulphur vacancies in MoS2 however is still controversial, with discrepancies in the literature pertaining to the origin of the in-gap features observed via scanning tunneling spectroscopy (STS) on single sulphur vacancies. Here we use a combination of scanning tunnelling microscopy (STM) and STS to study embedded sulphur vacancies in bulk MoS2 crystals. We observe spectroscopic features dispersing in real space and in energy, which we interpret as tip position- and bias-dependent ionization of the sulphur vacancy donor due to tip induced band bending (TIBB). The observations indicate that care must be taken in interpreting defect spectra as reflecting in-gap density of states, and may explain discrepancies in the literature.

Antiferromagnetic topological insulating state in Tb$_{0.02}$Bi$_{1.08}$Sb$_{0.9}$Te$_2$S single crystals. (arXiv:2307.09062v1 [cond-mat.mtrl-sci])
Lei Guo, Weiyao Zhao, Qile Li, Meng Xu, Lei Chen, Abdulhakim Bake, Thi-Hai-Yen Vu, Yahua He, Yong Fang, David Cortie, Sung-Kwan Mo, Mark Edmonds, Xiaolin Wang, Shuai Dong, Julie Karel, Ren-Kui Zheng

Topological insulators are emerging materials with insulating bulk and symmetry protected nontrivial surface states. One of the most fascinating transport behaviors in a topological insulator is the quantized anomalous Hall insulator, which has been observed inmagnetic-topological-insulator-based devices. In this work, we report a successful doping of rare earth element Tb into Bi$_{1.08}$Sb$_{0.9}$Te$_2$S topological insulator single crystals, in which the Tb moments are antiferromagnetically ordered below ~10 K. Benefiting from the in-bulk-gap Fermi level, transport behavior dominant by the topological surface states is observed below ~ 150 K. At low temperatures, strong Shubnikov-de Haas oscillations are observed, which exhibit 2D-like behavior. The topological insulator with long range magnetic ordering in rare earth doped Bi$_{1.08}$Sb$_{0.9}$Te$_2$S single crystal provides an ideal platform for quantum transport studies and potential applications.

Coexistence of Logarithmic and SdH Quantum Oscillations in Ferromagnetic Cr-doped Tellurium Single Crystals. (arXiv:2307.09139v1 [cond-mat.mtrl-sci])
Shu-Juan Zhang, Lei Chen, Shuang-Shuang Li, Ying Zhang, Jian-Min Yan, Fang Tang, Yong Fang, Lin-Feng Fei, Weiyao Zhao, Julie Karel, Yang Chai, Ren-Kui Zheng

We report the synthesis of transition-metal-doped ferromagnetic elemental single-crystal semiconductors with quantum oscillations using the physical vapor transport method. The 7.7 atom% Cr-doped Te crystals (Cr_Te) show ferromagnetism, butterfly-like negative magnetoresistance in the low temperature (< 3.8 K) and low field (< 0.15 T) region, and high Hall mobility, e.g., 1320 cm2 V-1 s-1 at 30 K and 350 cm2 V-1 s-1 at 300 K, implying that Cr_Te crystals are ferromagnetic elemental semiconductors. When B // c // I, the maximum negative MR is -27% at T = 20 K and B = 8 T. In the low temperature semiconducting region, Cr_Te crystals show strong discrete scale invariance dominated logarithmic quantum oscillations when the direction of the magnetic field B is parallel to the [100] crystallographic direction and show Landau quantization dominated Shubnikov-de Haas (SdH) oscillations for B // [210] direction, which suggests the broken rotation symmetry of the Fermi pockets in the Cr_Te crystals. The findings of coexistence of multiple quantum oscillations and ferromagnetism in such an elemental quantum material may inspire more study of narrow bandgap semiconductors with ferromagnetism and quantum phenomena.

Lecture Notes on Generalized Symmetries and Applications. (arXiv:2307.09215v1 [hep-th])
Ran Luo, Qing-Rui Wang, Yi-Nan Wang

In this lecture note, we give a basic introduction to the rapidly developing concepts of generalized symmetries, from the perspectives of both high energy physics and condensed matter physics. In particular, we emphasize on the (invertible) higher-form and higher-group symmetries. For the physical applications, we discuss the geometric engineering of QFTs in string theory and the symmetry-protected topological (SPT) phases in condensed matter physics.

The lecture note is based on a short course on generalized symmetries, jointly given by Yi-Nan Wang and Qing-Rui Wang in Feb. 2023, which took place at School of Physics, Peking University (

Dirac Landau levels for surfaces with constant negative curvature. (arXiv:2307.09221v1 [cond-mat.mes-hall])
Maximilian Fürst, Denis Kochan, Cosimo Gorini, Klaus Richter

Studies of the formation of Landau levels based on the Schr\"odinger equation for electrons constrained to curved surfaces have a long history. These include as prime examples surfaces with constant positive and negative curvature, the sphere [Phys. Rev. Lett. 51, 605 (1983)] and the pseudosphere [Annals of Physics 173, 185 (1987)]. Now, topological insulators, hosting Dirac-type surface states, provide a unique platform to experimentally examine such quantum Hall physics in curved space. Hence, extending previous work we consider solutions of the Dirac equation for the pseudosphere for both, the case of an overall perpendicular magnetic field and a homogeneous coaxial, thereby locally varying, magnetic field. For both magnetic-field configurations, we provide analytical solutions for spectra and eigenstates. For the experimentally relevant case of a coaxial magnetic field we find that the Landau levels split and show a peculiar scaling $\propto B^{1/4}$, thereby characteristically differing from the usual linear $B$ and $B^{1/2}$ dependence of the planar Schr\"odinger and Dirac case, respectively. We compare our analytical findings to numerical results that we also extend to the case of the Minding surface.

Vibrational dichroism of chiral valley phonons. (arXiv:2307.09280v1 [cond-mat.mes-hall])
Yiming Pan, Fabio Caruso

Valley degrees of freedom in transition-metal dichalcogenides influence thoroughly electron-phonon coupling and its nonequilibrium dynamics. We conducted a first-principles study of the quantum kinetics of chiral phonons following valley-selective carrier excitation with circularly-polarized light. Our numerical investigations treat the ultrafast dynamics of electrons and phonons on equal footing within a parameter-free ab-initio framework. We report the emergence of valley-polarized phonon populations in monolayer MoS$_2$ that can be selectively excited at either the K or K' valleys depending on the light helicity. The resulting vibrational state is characterized by a distinctive chirality, which lifts time-reversal symmetry of the lattice on transient timescales. We show that chiral valley phonons can further lead to fingerprints of vibrational dichroism detectable by ultrafast diffuse scattering and persisting beyond 10 ps. The valley polarization of nonequilibrium phonon populations could be exploited as information carrier, thereby extending the paradigm of valleytronics to the domain of vibrational excitations.

Analog of cosmological particle production in moir\'e Dirac materials. (arXiv:2307.09299v1 [cond-mat.mes-hall])
Mireia Tolosa-Simeón, Michael M. Scherer, Stefan Floerchinger

Moir\'e materials have recently been established experimentally as a highly-tunable condensed matter platform, facilitating the controlled manipulation of band structures and interactions. In several of these moir\'e materials, Dirac cones are present in the low-energy regime near the Fermi level. Thus, fermionic excitations emerging in these materials close to the Dirac cones have a linear dispersion relation near the Fermi surface as massless relativistic Dirac fermions. Here, we study low-energy fermionic excitations of moir\'e Dirac materials in the presence of a mass gap that may be generated by symmetry breaking. Introducing a dynamical Fermi velocity and/or time-dependent mass gap for the Dirac quasiparticles, we exhibit the emergence of an analog of cosmological fermion pair production in terms of observables such as the expected occupation number or two-point correlation functions. We find that it is necessary and sufficient for quasiparticle production that only the ratio between the mass gap and the Fermi velocity is time-dependent. In this way, we establish that moir\'e Dirac materials can serve as analog models for cosmological spacetime geometries, in particular, for Friedmann-Lema\^itre-Robertson-Walker expanding cosmologies. We briefly discuss possibilities for experimental realization.

(2+1)D SU(2) Yang-Mills Lattice Gauge Theory at finite density via tensor networks. (arXiv:2307.09396v1 [hep-lat])
Giovanni Cataldi, Giuseppe Magnifico, Pietro Silvi, Simone Montangero

We demonstrate the feasibility of Tensor Network simulations of non-Abelian lattice gauge theories in two spatial dimensions, by focusing on a (minimally truncated) SU(2) Yang-Mills model in Hamiltonian formulation, including dynamical matter. Thanks to our sign-problem-free approach, we characterize the phase diagram of the model at zero and finite baryon number, as a function of the bare mass and color charge of the quarks. Already at intermediate system sizes, we distinctly detect a liquid phase of quark-pair bound-state quasi-particles (baryons), whose mass is finite towards the continuum limit. Interesting phenomena arise at the transition boundary where color-electric and color-magnetic terms are maximally frustrated: for low quark masses, we see traces of potential deconfinement, while for high quark masses, we observe signatures of a possible topological order.

Metallic quantum criticality enabled by flat bands in a kagome lattice. (arXiv:2307.09431v1 [cond-mat.str-el])
Lei Chen, Fang Xie, Shouvik Sur, Haoyu Hu, Silke Paschen, Jennifer Cano, Qimiao Si

Strange metals arise in a variety of platforms for strongly correlated electrons, ranging from the cuprates, heavy fermions to flat band systems. Motivated by recent experiments in kagome metals, we study a Hubbard model on a kagome lattice whose noninteracting limit contains flat bands. A Kondo lattice description is constructed, in which the degrees of freedom are exponentially localized molecular orbitals. We identify an orbital-selective Mott transition through an extended dynamical mean field theory of the effective model. The transition describes a quantum critical point at which quasiparticles are expected to be lost and strange metallicity emerges. Our theoretical work opens up a new route for realizing beyond-Landau quantum criticality and emergent quantum phases that it nucleates.

Towards understanding the electronic structure of the simpler members of two-dimensional halide-perovskites. (arXiv:2307.09464v1 [cond-mat.mtrl-sci])
Efstratios Manousakis

In this paper we analyze the band-structure of two-dimensional (2D) halide perovskites by considering structures related to the simpler case of the series, (BA)$_2$PbI$_4$, in which PbI$_4$ layers are intercalated with butylammonium (BA=CH$_3$(CH$_2$)$_3$NH$_3$) organic ligands. We use density-functional-theory (DFT) based calculations and tight-binding (TB) models aiming to discover a simple description of the bands in the vicinity of the valence-band maximum and the conduction-band minimum. We find that the atomic orbitals of the butylammonium chains have negligible contribution to the Bloch states which form the conduction and valence bands in near the Fermi energy. Our calculations reveal a rather universal, i.e., independent of the intercalating BA, rigid-band picture characteristic of the layered perovskite ``matrix''. Besides demonstrating the above conclusion, the main goal of this paper is to find accurate TB models which capture the essential features of the DFT bands near the Fermi energy. First, we ignore electron hopping along the $c$-axis and the octahedral distortions and this increased symmetry halves the Bravais-lattice unit-cell size and the Brillouin zone unfolds to a 45$^{\circ}$ rotated square and this allows some analytical handling of the 2D TB-Hamiltonian. The Pb $6s$ and I $5s$ orbitals are far away from the Fermi level and, thus, we integrate them out to obtain an effective model which only includes hybridized Pb $6p$ and I $5p$ states. Our TB-based treatment a) provides a good quantitative description of the DFT band-structure, b) helps us conceptualize the complex electronic structure in the family of these materials in a simple way and c) yields the one-body part to be combined with appropriately screened electron interaction to describe many-body effects, such as excitonic bound-states.

Exact results for a boundary-driven double spin chain and resource-efficient remote entanglement stabilization. (arXiv:2307.09482v1 [quant-ph])
Andrew Lingenfelter, Mingxing Yao, Andrew Pocklington, Yu-Xin Wang, Abdullah Irfan, Wolfgang Pfaff, Aashish A. Clerk

We derive an exact solution for the steady state of a setup where two $XX$-coupled $N$-qubit spin chains (with possibly non-uniform couplings) are subject to boundary Rabi drives, and common boundary loss generated by a waveguide (either bidirectional or unidirectional). For a wide range of parameters, this system has a pure entangled steady state, providing a means for stabilizing remote multi-qubit entanglement without the use of squeezed light. Our solution also provides insights into a single boundary-driven dissipative $XX$ spin chain that maps to an interacting fermionic model. The non-equilibrium steady state exhibits surprising correlation effects, including an emergent pairing of hole excitations that arises from dynamically constrained hopping. Our system could be implemented in a number of experimental platforms, including circuit QED.

Novel phases in rotating Bose-condensed gas: vortices and quantum correlation. (arXiv:2206.14543v3 [cond-mat.quant-gas] UPDATED)
Mohd. Imran, M. A. H. Ahsan

We present the exact diagonalization study of rotating Bose-condensed gas interacting via finite-range Gaussian potential confined in a quasi-2D harmonic trap. The system of many-body Hamiltonian matrix is diagonalized in given subspaces of quantized total angular momentum to obtain the lowest-energy eigenstate employing the beyond lowest-Landau-level approximation. In the co-rotating frame, the quantum mechanical stability of angular momentum states is discussed for the existence of phase transition between the stable states of interacting system. Thereby analyzing the von Neumann entanglement entropy and degree of condensation provide the information about quantum phase correlation in the many-body states. Calculating the conditional probability distribution, we further probe the internal structure of quantum mechanically stable and unstable states. Much emphasis is put on finding the spatial correlation of bosonic atoms in the rotating system for the formation and entry of singly quantized vortices, and then organizing into canonical polygons with and without a central vortex at the trap center. Results are summarized in the form of a movie depicting the vortex patterns having discrete p-fold rotational symmetry with $p = 2,3,4,5,6$.

Exact Dirac-Bogoliubov-de Gennes Dynamics for Inhomogeneous Quantum Liquids. (arXiv:2208.14467v2 [cond-mat.stat-mech] UPDATED)
Per Moosavi

We study inhomogeneous 1+1-dimensional quantum many-body systems described by Tomonaga-Luttinger-liquid theory with general propagation velocity and Luttinger parameter varying smoothly in space, equivalent to an inhomogeneous compactification radius for free boson conformal field theory. This model appears prominently in low-energy descriptions, including for trapped ultra-cold atoms, while here we present an application to quantum Hall edges with inhomogeneous interactions. The dynamics is shown to be governed by a pair of coupled continuity equations identical to inhomogeneous Dirac-Bogoliubov-de Gennes equations with a local gap and solved by analytical means. We obtain their exact Green's functions and scattering matrix using a Magnus expansion, which generalize previous results for conformal interfaces and quantum wires coupled to leads. Our results explicitly describe the late-time evolution following quantum quenches, including inhomogeneous interaction quenches, and Andreev reflections between coupled quantum Hall edges, revealing a remarkably universal dependence on details at stationarity or at late times out of equilibrium.

Stability and asymptotic interactions of chiral magnetic skyrmions in a tilted magnetic field. (arXiv:2211.08017v2 [cond-mat.mes-hall] UPDATED)
Bruno Barton-Singer, Bernd J. Schroers

Using a general framework, interaction potentials between chiral magnetic solitons in a planar system with a tilted external magnetic field are calculated analytically in the limit of large separation. The results are compared to previous numerical results for solitons with topological charge $\pm 1$. A key feature of the calculation is the interpretation of Dzyaloshinskii-Moriya interaction (DMI) as a background $SO(3)$ gauge field. In a tilted field, this leads to a $U(1)$-gauged version of the usual equation for spin excitations, leading to a distinctive oscillating interaction profile. We also obtain predictions for skyrmion stability in a tilted field which closely match numerical observations.

Observation of time-reversal symmetric Hall effect in graphene-WSe2 heterostructures at room temperature. (arXiv:2301.01912v3 [cond-mat.mes-hall] UPDATED)
Priya Tiwari, Divya Sahani, Atasi Chakraborty, Kamal Das, Kenji Watanabe, Takashi Taniguchi, Amit Agarwal, Aveek Bid

In this letter, we provide experimental evidence of the time-reversal symmetric Hall effect in a mesoscopic system, namely high-mobility graphene/WSe$_2$ heterostructures. This linear, dissipative Hall effect, whose sign depends on the sign of the charge carriers, persists up to room temperature. The magnitude and the sign of the Hall signal can be tuned using an external perpendicular electric field. Our joint experimental and theoretical study establishes that the strain induced by lattice mismatch, or angle inhomogeneity, produces anisotropic bands in graphene while simultaneously breaking the inversion symmetry. The band anisotropy and reduced spatial symmetry lead to the appearance of a time-reversal symmetric Hall effect. Our study establishes graphene-transition metal dichalcogenide-based heterostructures as an excellent platform for studying the effects of broken symmetry on the physical properties of band-engineered two-dimensional systems.

Topological Hall effect in CeAlGe. (arXiv:2303.12144v2 [cond-mat.str-el] UPDATED)
M. M. Piva, J. C. Souza, G. A. Lombardi, K. R. Pakuszewski, C. Adriano, P. G. Pagliuso, M. Nicklas

The Weyl semimetal CeAlGe is a promising material to study nontrivial topologies in real and momentum space due to the presence of a topological magnetic phase. Our results at ambient pressure show that the electronic properties of CeAlGe are extremely sensitive to small stoichiometric variations. In particular, the topological Hall effect (THE) present in CeAlGe is absent in some samples of almost identical chemical composition. The application of external pressure favors the antiferromagnetic ground state. It also induces a THE where it was not visible at ambient pressure. Furthermore, a small pressure is sufficient to drive the single region of the THE in magnetic fields into two different ones. Our results reveal an extreme sensitivity of the electronic properties of CeAlGe to tiny changes in its chemical composition, leading to a high tunability by external stimuli. We can relate this sensitivity to a shift in the Fermi level and to domain walls.

Second spectrum of charge carrier density fluctuations in graphene due to trapping/detrapping processes. (arXiv:2305.07628v2 [cond-mat.mes-hall] UPDATED)
Francesco M. D. Pellegrino, Giuseppe Falci, Elisabetta Paladino

We investigate the second spectrum of charge carrier density fluctuations in graphene within the McWorther model, where noise is induced by electron traps in the substrate. Within this simple picture, we obtain a closed-form expression including both Gaussian and non-Gaussian fluctuations. We show that a very extended distribution of switching rates of the electron traps in the substrate leads to a carrier density power spectrum with a non-trivial structure on the scale of the measurement bandwidth. This explains the appearance of a $1/f$ component in the Gaussian part of the second spectrum, which adds up to the expected frequency-independent term. Finally, we find that the non-Gaussian part of the second spectrum can become quantitatively relevant by approaching extremely low temperatures.

Eight-dimensional topological systems simulated using time-space crystalline structures. (arXiv:2305.07668v2 [cond-mat.quant-gas] UPDATED)
Yakov Braver, Egidijus Anisimovas, Krzysztof Sacha

We demonstrate the possibility of using time-space crystalline structures to simulate eight-dimensional systems based on only two physical dimensions. A suitable choice of system parameters allows us to obtain a gapped energy spectrum, making topological effects become relevant. The nontrivial topology of the system is evinced by considering the adiabatic state pumping along temporal and spatial crystalline directions. Analysis of the system is facilitated by rewriting the system Hamiltonian in a tight-binding form, thereby putting space, time, and the additional synthetic dimensions on an equal footing.

The Composite Particle Duality: A New Class of Topological Quantum Matter. (arXiv:2306.00825v2 [cond-mat.str-el] UPDATED)
Gerard Valentí-Rojas, Joel Priestley, Patrik Öhberg

The composite particle duality extends the notions of both flux attachment and statistical transmutation in spacetime dimensions beyond 2+1$\text{D}$. It constitutes an exact correspondence that can be understood either as a theoretical framework or as a dynamical physical mechanism. The immediate implication of the duality is that an interacting quantum system in arbitrary dimensions can experience a modification of its statistical properties if coupled to a certain gauge field. In other words, commutation relations of quantum fields can be effectively modified by a dynamical physical process. For instance, an originally bosonic quantum fluid in d spatial dimensions can feature composite fermionic (or anyonic) excitations when coupled to a statistical gauge field. We compute the explicit form of the aforementioned synthetic gauge fields in $\text{D} \le 3 + 1$. This opens the door to a new realm of topological phases across dimensions both in lattice and continuum systems.

Ultrafast Hidden Spin Polarization Dynamics of Bright and Dark Excitons in 2H-WSe$_2$. (arXiv:2306.03610v2 [cond-mat.mes-hall] UPDATED)
Mauro Fanciulli, David Bresteau, Jérome Gaudin, Shuo Dong, Romain Géneaux, Thierry Ruchon, Olivier Tcherbakoff, Ján Minár, Olivier Heckmann, Maria Christine Richter, Karol Hricovini, Samuel Beaulieu

We performed spin-, time- and angle-resolved extreme ultraviolet photoemission spectroscopy (STARPES) of excitons prepared by photoexcitation of inversion-symmetric 2H-WSe$_2$ with circularly polarized light. The very short probing depth of XUV photoemission permits selective measurement of photoelectrons originating from the top-most WSe$_2$ layer, allowing for direct measurement of hidden spin polarization of bright and momentum-forbidden dark excitons. Our results reveal efficient chiroptical control of bright excitons' hidden spin polarization. Following optical photoexcitation, intervalley scattering between nonequivalent K-K' valleys leads to a decay of bright excitons' hidden spin polarization. Conversely, the ultrafast formation of momentum-forbidden dark excitons acts as a local spin polarization reservoir, which could be used for spin injection in van der Waals heterostructures involving multilayer transition metal dichalcogenides.

Synthetic gauge fields enable high-order topology on Brillouin real projective plane. (arXiv:2306.15477v2 [cond-mat.mes-hall] UPDATED)
Jinbing Hu, Songlin Zhuang, Yi Yang

The topology of the Brillouin zone, foundational in topological physics, is always assumed to be a torus. We theoretically report the construction of Brillouin real projective plane ($\mathrm{RP}^2$) and the appearance of quadrupole insulating phase, which are enabled by momentum-space nonsymmorphic symmetries stemming from $\mathbb{Z}_2$ synthetic gauge fields. We show that the momentum-space nonsymmorphic symmetries quantize bulk polarization and Wannier-sector polarization nonlocally across different momenta, resulting in quantized corner charges and an isotropic binary bulk quadrupole phase diagram, where the phase transition is triggered by a bulk energy gap closing. Under open boundary conditions, the nontrivial bulk quadrupole phase manifests either trivial or nontrivial edge polarization, resulting from the violation of momentum-space nonsymmorphic symmetries under lattice termination. We present a concrete design for the $\mathrm{RP}^2$ quadrupole insulator based on acoustic resonator arrays and discuss its feasibility in optics, mechanics, and electrical circuits. Our results show that deforming the Brillouin manifold creates opportunities for realizing high-order band topology.

Vortex loop dynamics and dynamical quantum phase transitions in 3D fermion matter. (arXiv:2307.02985v2 [cond-mat.stat-mech] UPDATED)
Arkadiusz Kosior, Markus Heyl

In this study, we investigate the behavior of vortex singularities in the phase of the Green's function of a general non-interacting fermionic lattice model in three dimensions after an instantaneous quench. We find that the full set of vortices form one-dimensional dynamical objects, which we call vortex loops. The number of such vortex loops can be interpreted as a quantized order parameter that distinguishes between different non-equilibrium phases. We show that changes in this order parameter are related to dynamical quantum phase transitions (DQPTs). Our results are applicable to general lattice models in three dimensions. For concreteness, we present them in the context of a simple two-band Weyl semimetal. We also show that the vortex loops survive in weakly interacting systems. Finally, we observe that vortex loops can form complex dynamical patterns in momentum space due to the existence of band touching Weyl nodes. Our findings provide valuable insights for developing definitions of dynamical order parameters in non-equilibrium systems.

Biorthogonal dynamical quantum phase transitions in non-Hermitian systems. (arXiv:2307.02993v2 [quant-ph] UPDATED)
Yecheng Jing, Jian-Jun Dong, Yu-Yu Zhang, Zi-Xiang Hu

By using biorthogonal bases, we construct a complete framework for biorthogonal dynamical quantum phase transitions in non-Hermitian systems. With the help of associated state which is overlooked previously, we define the automatically normalized biorthogonal Loschmidt echo. This approach is capable of handling arbitrary non-Hermitian systems with complex eigenvalues, which naturally eliminates the negative value of Loschmidt rate obtained without the biorthogonal bases. Taking the non-Hermitian Su-Schrieffer-Heeger model as a concrete example, a peculiar $1/2$ change in biorthogonal dynamical topological order parameter, which is beyond the traditional dynamical quantum phase transitions is observed. We also find the periodicity of biorthogonal dynamical quantum phase transitions depend on whether the two-level subsystem at the critical momentum oscillates or reaches a steady state.

Photoinduced High-Chern-Number Quantum Anomalous Hall Effect from Higher-Order Topological Insulators. (arXiv:2307.07116v2 [cond-mat.mes-hall] UPDATED)
Xiaolin Wan, Zhen Ning, Dong-Hui Xu, Baobing Zheng, Rui Wang

Quantum anomalous Hall (QAH) insulators with high Chern number host multiple dissipationless chiral edge channels, which are of fundamental interest and promising for applications in spintronics and quantum computing. However, only a limited number of high-Chern-number QAH insulators have been reported to date. Here, we propose a dynamic approach for achieving high-Chern-number QAH phases in periodically driven two-dimensional higher-order topological insulators (HOTIs).In particular, we consider two representative kinds of HOTIs which are characterized by a quantized quadruple moment and the second Stiefel-Whitney number, respectively. Using the Floquet formalism for periodically driven systems, we demonstrate that QAH insulators with tunable Chern number up to four can be achieved. Moreover, we show by first-principles calculations that the monolayer graphdiyne, a realistic HOTI, is an ideal material candidate. Our work not only establishes a strategy for designing high-Chern-number QAH insulators in periodically driven HOTIs, but also provides a powerful approach to investigate exotic topological states in nonequilibrium cases.

Dynamical simulation of the injection of vortices into a Majorana edge mode. (arXiv:2307.07447v2 [cond-mat.mes-hall] UPDATED)
I. M. Flor, A. Donis Vela, C. W. J. Beenakker, G. Lemut

The chiral edge modes of a topological superconductor can transport fermionic quasiparticles, with Abelian exchange statistics, but they can also transport non-Abelian anyons: Majorana zero-modes bound to a {\pi}-phase domain wall that propagates along the boundary. Such an edge vortex is injected by the application of an h/2e flux bias over a Josephson junction. Existing descriptions of the injection process rely on the instantaneous scattering approximation of the adiabatic regime, where the internal dynamics of the Josephson junction is ignored. Here we go beyond that approximation in a time-dependent many-body simulation of the injection process, followed by a braiding of the mobile edge vortex with an immobile Abrikosov vortex in the bulk of the superconductor. Our simulation sheds light on the properties of the Josephson junction needed for a successful implementation of a flying Majorana qubit.

Found 8 papers in prb
Date of feed: Wed, 19 Jul 2023 03:17:07 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]+)

Topological triple phase transition in non-Hermitian quasicrystals with complex asymmetric hopping
Shaina Gandhi and Jayendra N. Bandyopadhyay
Author(s): Shaina Gandhi and Jayendra N. Bandyopadhyay

The triple phase transitions or simultaneous transitions of three different phases, namely, topological, parity-time $(\mathcal{P}\mathcal{T})$ symmetry breaking, and metal-insulator transitions, are observed in an extension of the $\mathcal{P}\mathcal{T}$ symmetric non-Hermitian Aubry-André-Harper …

[Phys. Rev. B 108, 014204] Published Tue Jul 18, 2023

Nonthermoelastic martensitic features in ideal martensites due to volume effects
Yuanchao Yang, Yangyang Xu, Yumei Zhou, Xiangdong Ding, Jun Sun, Turab Lookman, and Dezhen Xue
Author(s): Yuanchao Yang, Yangyang Xu, Yumei Zhou, Xiangdong Ding, Jun Sun, Turab Lookman, and Dezhen Xue

We study martensitic transformation behavior by considering the coupling of volumetric strain and the transformation strain in a group-subgroup transformation within a Ginzburg-Landau framework. Nonthermoelastic features, including large residual strain, large thermal hysteresis, and incomplete tran…

[Phys. Rev. B 108, 024102] Published Tue Jul 18, 2023

Incommensurate magnetic order in the ${\mathbb{Z}}_{2}$ kagome metal ${\mathrm{GdV}}_{6}{\mathrm{Sn}}_{6}$
Zach Porter, Ganesh Pokharel, Jong-Woo Kim, Phillip J. Ryan, and Stephen D. Wilson
Author(s): Zach Porter, Ganesh Pokharel, Jong-Woo Kim, Phillip J. Ryan, and Stephen D. Wilson

We characterize the magnetic ground state of the topological kagome metal ${\mathrm{GdV}}_{6}{\mathrm{Sn}}_{6}$ via resonant x-ray diffraction. Previous magnetoentropic studies of ${\mathrm{GdV}}_{6}{\mathrm{Sn}}_{6}$ suggested the presence of a modulated magnetic order distinct from the ferromagnet…

[Phys. Rev. B 108, 035134] Published Tue Jul 18, 2023

Triplet pair density wave superconductivity on the $π$-flux square lattice
Daniel Shaffer and Luiz H. Santos
Author(s): Daniel Shaffer and Luiz H. Santos

Pair-density waves (PDWs) are superconducting states that spontaneously break translation symmetry in systems with time-reversal symmetry (TRS). Evidence for PDWs has been seen in several recent experiments, as well as in the pseudogap regime in cuprates. Theoretical understanding of PDWs has been l…

[Phys. Rev. B 108, 035135] Published Tue Jul 18, 2023

Partial fillings of the bosonic ${E}_{8}$ quantum Hall state
Pak Kau Lim, Michael Mulligan, and Jeffrey C. Y. Teo
Author(s): Pak Kau Lim, Michael Mulligan, and Jeffrey C. Y. Teo

Interactions are crucial for topological phenomena in bosonic systems. Some condenses bosons, like helium-4, into a symmetry breaking phase. Instead, the authors construct here exactly solvable models of interacting bosons that preserve charge conservation. They focus on the E8 bosonic integer quantum Hall state, and show that the intrinsic E8 symmetry allows the emergence of fractional topological phases of bosons. They detail charge and statistics of the excitations of the resulting fractional phases.

[Phys. Rev. B 108, 035136] Published Tue Jul 18, 2023

Effective $\mathbf{k}·\mathbf{p}$ model of monolayer $1{T}^{′}\text{−}{\mathrm{MoS}}_{2}$ under perpendicular electric field
Ma Zhou, Sheng-bin Yu, An-hua Huang, Li Wang, and Kai Chang
Author(s): Ma Zhou, Sheng-bin Yu, An-hua Huang, Li Wang, and Kai Chang

We derive the effective $\mathbf{k}·\mathbf{p}$ Hamiltonian for an electron in monolayer ${T}^{′}\text{−}{\mathrm{MoS}}_{2}$ near the Fermi level in the presence of spin-orbit coupling and a perpendicular electric field. The $4×4\phantom{\rule{4pt}{0ex}}\mathbf{k}·\mathbf{p}$ Hamiltonian is capable …

[Phys. Rev. B 108, 035412] Published Tue Jul 18, 2023

Strain-dependent electronic and mechanical properties in one-dimensional topological insulator ${\mathrm{Nb}}_{4}{\mathrm{SiTe}}_{4}$
Siyuan Liu, Huabing Yin, and Peng-Fei Liu
Author(s): Siyuan Liu, Huabing Yin, and Peng-Fei Liu

Topological insulators hold great promise for dissipationless transport devices due to the robust gapless states inside the insulating bulk gap. So far, several generations of topological insulators have been theoretically predicted and experimentally confirmed, most of them based on three- or two-d…

[Phys. Rev. B 108, 045411] Published Tue Jul 18, 2023

Spin-statistics relation for quantum Hall states
Alberto Nardin, Eddy Ardonne, and Leonardo Mazza
Author(s): Alberto Nardin, Eddy Ardonne, and Leonardo Mazza

Forty years ago, Laughlin explained the newly discovered fractional quantum Hall effect by proposing his famous wave function. He predicted the existence of anyons, particles with fractional charge, obeying fractional statistics. The fractional charge was confirmed almost thirty years ago, while the fractional statistics was observed only a few years back. In this paper, the authors focus on yet another fundamental property of the anyons, namely their spin. They derive a “spin-statistics relation” for anyons in fractional quantum Hall states, directly from the microscopic theory. This relation is a generalization of the fundamental “spin-statistics relation” that all ordinary particles obey.

[Phys. Rev. B 108, L041105] Published Tue Jul 18, 2023

Found 1 papers in prl
Date of feed: Wed, 19 Jul 2023 03:17:05 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]+)

Engineering SYK Interactions in Disordered Graphene Flakes under Realistic Experimental Conditions
Marta Brzezińska, Yifei Guan, Oleg V. Yazyev, Subir Sachdev, and Alexander Kruchkov
Author(s): Marta Brzezińska, Yifei Guan, Oleg V. Yazyev, Subir Sachdev, and Alexander Kruchkov

We model interactions following the Sachdev-Ye-Kitaev (SYK) framework in disordered graphene flakes up to 300 000 atoms in size ($∼100\text{ }\text{ }\mathrm{nm}$ in diameter) subjected to an out-of-plane magnetic field $B$ of 5–20 Tesla within the tight-binding formalism. We investigate two sources…

[Phys. Rev. Lett. 131, 036503] Published Tue Jul 18, 2023

Found 2 papers in nano-lett
Date of feed: Tue, 18 Jul 2023 13:06:36 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]+)

[ASAP] Giant and Tunable Out-of-Plane Spin Polarization of Topological Antimonene
Polina M. Sheverdyaeva, Conor Hogan, Gustav Bihlmayer, Jun Fujii, Ivana Vobornik, Matteo Jugovac, Asish K. Kundu, Sandra Gardonio, Zipporah Rini Benher, Giovanni Di Santo, Sara Gonzalez, Luca Petaccia, Carlo Carbone, and Paolo Moras

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Nano Letters
DOI: 10.1021/acs.nanolett.3c00153

[ASAP] Dirac Half-Semimetallicity and Antiferromagnetism in Graphene Nanoribbon/Hexagonal Boron Nitride Heterojunctions
Nikita V. Tepliakov, Ruize Ma, Johannes Lischner, Efthimios Kaxiras, Arash A. Mostofi, and Michele Pizzochero

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Nano Letters
DOI: 10.1021/acs.nanolett.3c01940

Found 1 papers in acs-nano
Date of feed: Tue, 18 Jul 2023 13:03:24 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]+)

[ASAP] Mobility Enhancement of Strained MoS2 Transistor on Flat Substrate
Yang Chen, Donglin Lu, Lingan Kong, Quanyang Tao, Likuan Ma, Liting Liu, Zheyi Lu, Zhiwei Li, Ruixia Wu, Xidong Duan, Lei Liao, and Yuan Liu

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ACS Nano
DOI: 10.1021/acsnano.3c03626

Found 1 papers in sci-rep

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]+)

Author Correction: Testing pseudotopological and nontopological models for SMC-driven DNA loop extrusion against roadblock-traversal experiments
Cees Dekker

Scientific Reports, Published online: 18 July 2023; doi:10.1038/s41598-023-38687-5

Author Correction: Testing pseudotopological and nontopological models for SMC-driven DNA loop extrusion against roadblock-traversal experiments

Found 1 papers in nat-comm

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)

Topotactic fabrication of transition metal dichalcogenide superconducting nanocircuits
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