Found 31 papers in cond-mat
Date of feed: Thu, 19 Oct 2023 00:30:00 GMT

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Quantum geometry induced nonlinear transport in altermagnets. (arXiv:2310.11489v1 [cond-mat.mes-hall])
Yuan Fang, Jennifer Cano, Sayed Ali Akbar Ghorashi

Quantum geometry plays a pivotal role in the second-order response of $\cal PT$-symmetric antiferromagnets. Here we study the nonlinear response of 2D altermagnets protected by $C_n\cal T$ symmetry and show that their leading nonlinear response is third-order. Furthermore, we show that the contributions from the quantum metric and Berry curvature enter separately: the longitudinal response for all planar altermagnets \emph{only} has a contribution from the quantum metric quadrupole (QMQ), while transverse responses in general have contributions from both the Berry curvature quadrupole (BCQ) and QMQ. We show that for the well-known example of $d$-wave altermagnets the Hall response is dominated by the BCQ. Both longitudinal and transverse responses are strongly dependent on the crystalline anisotropy. While altermagnets are strictly defined in the limit of vanishing SOC, real altermagnets exhibit weak SOC, which is essential to observe this response. Specifically, SOC gaps the spin-group protected nodal line, generating a response peak that is sharpest when SOC is weak. Two Dirac nodes also contribute a divergence to the nonlinear response, whose scaling changes as a function of SOC. Finally, we apply our results to thin films of the 3D altermagnet RuO$_2$. Our work uncovers distinct features of altermagnets in nonlinear transport, providing experimental signatures as well as a guide to disentangling the different components of their quantum geometry.

Intertwined fractional quantum anomalous Hall states and charge density waves. (arXiv:2310.11632v1 [cond-mat.str-el])
Xue-Yang Song, Chao-Ming Jian, Liang Fu, Cenke Xu

Motivated by the recent experimental breakthrough on the observation of the fractional quantum anomalous Hall (FQAH) effects in semiconductor and graphene moir\'{e} materials, we explore the rich physics associated with the intertwinement between FQAH effect and the charge density wave (CDW) order that spontaneously breaks the translation symmetry. We refer to a state with coexisting FQAH effect and CDW order as "FQAH-crystal". We show that the interplay between FQAH effect and CDW can lead to a rich phase diagram including multiple topological phases and topological quantum phase transitions at the same moir\'e filling. In particular, we demonstrate the possibility of direct quantum phase transitions from a FQAH-crystal with Hall conductivity $\sigma_H = - 2/3$ to a trivial CDW insulator with $\sigma_H = 0$, and more interestingly, to a QAH-crystal with $\sigma_H= -1$.

Towards a Topological Classification of Nonadiabaticity in Chemical Reactions. (arXiv:2310.11633v1 [cond-mat.mtrl-sci])
Christopher Daggett, Kaijie Yang, Chaoxing Liu, Lukas Muechler

The application of topology, a branch of mathematics, to the study of electronic states in crystalline materials has had a revolutionary impact on the field of condensed matter physics. For example, the development of topological band theory has delivered new approaches and tools to characterize the electronic structure of materials, resulting in the discovery of new phases of matter with exotic properties. In the framework of topological band theory, the crossings between energy levels of electrons are characterized by topological invariants, which predict the presence of topological boundary states. Given the frequency of energy level crossings on the potential energy surface in molecules, the applicability of these concepts to molecular systems could be of great interest for our understanding of reaction dynamics. However, challenges arise due to differing quantum mechanical descriptions of solids and molecules. Out work aims to bridge the gap between topological band theory and molecular chemistry. We propose that the Euler Class, a topological invariant, can be used to categorize and analyse the distribution of nonadiabatic couplings on the potential energy surface. To exemplify this connection, we introduce a model system with two distinct regimes that are characterized by different values of the Euler Class, yet identical potential energy surfaces. Contrary to expectations set by the Born-Oppenheimer approximation, we propose that these two regimes don't exhibit identical dynamics, due to a qualitatively distinct distribution of nonadiabatic couplings.

Dirac quantum spin liquid emerging in a kagome-lattice antiferromagnet. (arXiv:2310.11646v1 [cond-mat.str-el])
Zhenyuan Zeng, Chengkang Zhou, Honglin Zhou, Lankun Han, Runze Chi, Kuo Li, Maiko Kofu, Kenji Nakajima, Yuan Wei, Wenliang Zhang, D. G. Mazzone, Zi Yang Meng, Shiliang Li

Emerging quasi-particles with Dirac dispersion in condensed matter physics are analogous to their cousins in high-energy physics in that both of them can be described by the Dirac equation for relativistic electrons. Recently, these Dirac fermions have been widely found in electronic systems, such as graphene and topological insulators. At the conceptual level, since the charge is not a prerequisite for Dirac fermions, the emergence of Dirac fermions without charge degree of freedom has been theoretically predicted to be realized in Dirac quantum spin liquids. In such case, the Dirac quasiparticles are charge-neutral and carry a spin of 1/2, known as spinons. Despite of theoretical aspirations, spectra evidence of Dirac spinons remains elusive. Here we show that the spin excitations of a kagome antiferromagnet, YCu$_3$(OD)$_6$Br$_2$[Br$_{x}$(OD)$_{1-x}$], are conical with a spin continuum inside, which are consistent with the convolution of two Dirac spinons. The spinon velocity obtained from the spin excitations also quantitatively reproduces the low-temperature specific heat of the sample. Interestingly, the locations of the conical spin excitations differ from those calculated by the nearest neighbor Heisenberg model, suggesting an unexpected origin of the Dirac spinons. Our results thus provide strong spectra evidence for the Dirac quantum-spin-liquid state emerging in this kagome-lattice antiferromagnet.

Chiral topological metals with multiple types of quasiparticle fermions and large spin Hall effect in the SrGePt family materials. (arXiv:2310.11668v1 [cond-mat.mtrl-sci])
Yi Shen, Yahui Jin, Yongheng Ge, Mingxing Chen, Ziming Zhu

We present a prediction of chiral topological metals with several classes of unconventional quasiparticle fermions in a family of SrGePt-type materials in terms of first-principles calculations. In these materials, fourfold spin-3/2 Rarita-Schwinger-Weyl (RSW) fermion, sixfold excitation, and Weyl fermions coexist around the Fermi level as spin-orbit coupling is considered, and the Chern number for the first two kinds of fermions is the maximal value four. We found that large Fermi arcs from spin-3/2 RSW fermion emerge on the (010)-surface, spanning the whole surface Brillouin zone. Moreover, there exist Fermi arcs originating from Weyl points, which further overlap with trivial bulk bands. In addition, we revealed that the large spin Hall conductivity can be obtained, which attributed to the remarkable spin Berry curvature around the degenerate nodes and band-splitting induced by spin-orbit coupling. Our findings indicate that the SrGePt family of compounds provide an excellent platform for studying on topological electronic states and the intrinsic spin Hall effect.

Magnetic eight-fold nodal-point and nodal-network fermions in MnB2. (arXiv:2310.11669v1 [cond-mat.mtrl-sci])
Yongheng Ge, Ziming Zhu, Zeying Zhang, Weikang Wu, Cong Xiao, Shengyuan A. Yang

Realizing topological semimetal states with novel emergent fermions in magnetic materials is a focus of current research. Based on first-principle calculations and symmetry analysis, we reveal interesting magnetic emergent fermions in an existing material MnB2. In the temperature range from 157 K to 760 K, MnB2 is a collinear antiferromagnet. We find the coexistence of eightfold nodal points and nodal net close to the Fermi level, which are protected by the spin group in the absence of spin-orbit coupling. Depending on the Neel vector orientation, consideration of spin-orbit coupling will either open small gaps at these nodal features, or transform them into magnetic linear and quadratic Dirac points and nodal rings. Below 157 K, MnB2 acquires weak ferromagnetism due to spin tilting. We predict that this transition is accompanied by a drastic change in anomalous Hall response, from zero above 157 K to 200 $\Omega\cdot \text{cm}^{-1}$ below 157 K.

Moire synaptic transistor for homogeneous-architecture reservoir computing. (arXiv:2310.11743v1 [cond-mat.mes-hall])
Pengfei Wang, Moyu Chen, Yongqin Xie, Chen Pan, Kenji Watanabe, Takashi Taniguchi, Bin Cheng, Shi-Jun Liang, Feng Miao

Reservoir computing has been considered as a promising intelligent computing paradigm for effectively processing complex temporal information. Exploiting tunable and reproducible dynamics in the single electronic device have been desired to implement the reservoir and the readout layer of reservoir computing system. Two-dimensional moire material, with an artificial lattice constant many times larger than the atomic length scale, is one type of most studied artificial quantum materials in community of material science and condensed-matter physics over the past years. These materials are featured with gate-tunable periodic potential and electronic correlation, thus varying the electric field allows the electrons in the moire potential per unit cell to exhibit distinct and reproducible dynamics, showing great promise in robust reservoir computing. Here, we report that a moire synaptic transistor can be used to implement the reservoir computing system with a homogeneous reservoir-readout architecture. The synaptic transistor is fabricated based on a h-BN/bilayer graphene/h-BN moire heterostructure, exhibiting ferroelectricity-like hysteretic gate voltage dependence of resistance. Varying the magnitude of the gate voltage enables the moire transistor to be switched between long-term memory and short-term memory with nonlinear dynamics. By employing the short- and long-term memory as the reservoir nodes and weights of the readout layer, respectively, we construct a full-moire physical neural network and demonstrate that the classification accuracy of 90.8% can be achieved for the MNIST handwritten digit database. Our work would pave the way towards the development of neuromorphic computing based on the moire materials.

Topological phase locking in dissipatively-coupled noise-activated processes. (arXiv:2310.11788v1 [cond-mat.stat-mech])
Michalis Chatzittofi, Ramin Golestanian, Jaime Agudo-Canalejo

We study a minimal model of two non-identical noise-activated oscillators that interact with each other through a dissipative coupling. We find that the system exhibits a rich variety of dynamical behaviors, including a novel phase-locking phenomenon that we term topological phase locking (TPL). TPL is characterized by the emergence of a band of periodic orbits that form a torus knot in phase space, along which the two oscillators advance in rational multiples of each other, which coexists with the basin of attraction of the stable fixed point. We show that TPL arises as a result of a complex hierarchy of global bifurcations. Even if the system remains noise-activated, the existence of the band of periodic orbits enables effectively deterministic dynamics, resulting in a greatly enhanced speed of the oscillators. Our results have implications for understanding the dynamics of a wide range of systems, from biological enzymes and molecular motors to engineered electronic, optical, or mechanical oscillators.

Quadratic nodal point in a two-dimensional noncollinear antiferromagnet. (arXiv:2310.11810v1 [cond-mat.mes-hall])
Xukun Feng, Zeying Zhang, Weikang Wu, Xian-Lei Sheng, Shengyuan A. Yang

Quadratic nodal point (QNP) in two dimensions has so far been reported only in nonmagnetic materials and in the absence of spin-orbit coupling. Here, by first-principles calculations and symmetry analysis, we predict stable QNP near Fermi level in a two-dimensional kagome metal-organic framework material, Cr$_3$(HAB)$_2$, which features noncollinear antiferromagnetic ordering and sizable spin-orbit coupling. Effective kp and lattice models are constructed to capture such magnetic QNPs. Besides QNP, we find Cr$_3$(HAB)$_2$ also hosts six magnetic linear nodal points protected by mirror as well as $C_{2z}T$ symmetry. Properties associated to these nodal points, such as topological edge states and quantized optical absorbance, are discussed.

Structures and Electronic States of Nickel Rich Oxides for Lithium Ion Batteries. (arXiv:2310.11856v1 [cond-mat.mtrl-sci])
Saleem Yousuf, Md Maruf Mridha, Rita Magri

A new superstructure of layered pristine LiNiO2 (LNO) was obtained optimizing a large supercell of the 166 space group, the one observed experimentally by XRD, and relaxing both cell parameters and internal positions. The crystal structure shows size and charge disproportionation of the NiO6 octahedra instead of the Jahn-Teller distortion. The decrease of the internal energy obtained with the structural optimization of the supercell relative to the same structure in its primitive unit cell is much larger than the one obtained by relaxing similarly dimensioned supercells of monoclinic symmetry relative to their primitive unit cells, although the monoclinic phase remains more stable. The Ni-O bond length distribution of the new structure agree well with the experiments. Our results show that the choice of the simulation cell is important for determining the energetics of this class of oxide materials, proposed for cathodes in lithium ion batteries (LIBs). We used this new structure as a template for the study of the structural and electronic changes induced by the delithiation and Mn for Ni cation substitution, originating the solid solutions LiNiyMn(1-y)O2 (LNMO). Our results, surprisingly, agree well with the existing experiments and explain observed trends better than previous studies.

Multiple flat bands and localized states in photonic super-Kagome lattices. (arXiv:2310.11858v1 [physics.optics])
Limin Song, Shenyi Gao, Jina Ma, Liqin Tang, Daohong Song, Yigang Li, Zhigang Chen

We demonstrate multiple flat bands and compact localized states (CLSs) in a photonic super-Kagome lattice (SKL) that exhibits coexistence of singular and nonsingular flat bands within its unique band structure. Specifically, we find that the upper two flat bands of an SKL are singular - characterized by singularities due to band touching with their neighboring dispersive bands at the Brillouin zone center. Conversely, the lower three degenerate flat bands are nonsingular, and remain spectrally isolated from other dispersive bands. The existence of such two distinct types of flat bands is experimentally demonstrated by observing stable evolution of the CLSs with various geometrical shapes in a laser-written SKL. We also discuss the classification of the flat bands in momentum space, using band-touching singularities of the Bloch wave functions. Furthermore, we validate this classification in real space based on unit cell occupancy of the CLSs in a single SKL plaquette. These results may provide insights for the study of flatband transport, dynamics, and nontrivial topological phenomena in other relevant systems.

Structural transformations driven by local disorder at interfaces. (arXiv:2310.11863v1 [cond-mat.mtrl-sci])
Yanyan Liang, Grisell Díaz Leines, Ralf Drautz, Jutta Rogal

Despite the fundamental importance of solid-solid transformations in many technologies, the microscopic mechanisms remain poorly understood. Here, we explore the atomistic mechanisms at the migrating interface during solid-solid phase transformations between the topologically closed-packed A15 and body-centred cubic phase in tungsten. The high energy barriers and slow dynamics associated with this transformation require the application of enhanced molecular sampling approaches. To this end, we performed metadynamics simulations in combination with a path collective variable derived from a machine learning classification of local structural environments, which allows the system to freely sample the complex interface structure. A disordered region of varying width forming at the migrating interface is identified as a key physical descriptor of the transformation mechanisms, facilitating the atomic shuffling and rearrangement necessary for structural transformations. Furthermore, this can directly be linked to the differences in interface mobility for distinct orientation relationships as well as the formation of interfacial ledges during the migration along low-mobility directions.

Pseudo Electric Field and Pumping Valley Current in Graphene Nano-bubbles. (arXiv:2310.11904v1 [cond-mat.mes-hall])
Naif Hadadi, Adel Belayadi, Ahmed AlRabiah, Ousmane Ly, Collins Ashu Akosa, Michael Vogl, Hocine Bahlouli, Aurelien Manchon, Adel Abbout

The extremely high pseudo-magnetic field emerging in strained graphene suggests that an oscillating nano-deformation will induce a very high current even without electric bias. In this paper, we demonstrate the sub-terahertz (THz) dynamics of a valley-current and the corresponding charge pumping with a periodically excited nano-bubble. We discuss the amplitude of the pseudo-electric field and investigate the dependence of the pumped valley current on the different parameters of the system. Finally, we report the signature of extra-harmonics generation in the valley current that might lead to potential modern devices development operating in the nonlinear regime

Valley-dependent tunneling through electrostatically created quantum dots in heterostructures of graphene with hexagonal boron nitride. (arXiv:2310.11941v1 [cond-mat.mes-hall])
A. Belayadi, N. A. Hadadi, P. Vasilopoulos, A. Abbout

Kelvin probe force microscopy (KPFM) has been employed to probe charge carriers in a graphene/hexagonal boron nitride (hBN) heterostructure [Nano Lett, 21, 5013 (2021)]. We propose an approach for operating valley filtering based on the KPFM-induced potential $U_0$ instead of using external or induced pseudo-magnetic fields in strained graphene. Employing a tight-binding model, we investigate the parameters and rules leading to valley filtering in the presence of a graphene quantum dot (GQD) created by the KPFM tip. This model leads to a resolution of different transport channels in reciprocal space, where the electron transmission probability at each Dirac cone ($K_1$= -K and $K_2$ = +K) is evaluated separately. The results show that U0 and the Fermi energy $E_F$ control (or invert) the valley polarization, if electrons are allowed to flow through a given valley. The resulting valley filtering is allowed only if the signs of $E_F$ and $U_0$ are the same. If they are different, the valley filtering is destroyed and might occur only at some resonant states affected by $U_0$. Additionally, there are independent valley modes characterizing the conductance oscillations near the vicinity of the resonances, whose strength increases with $U_0$ and are similar to those occurring in resonant tunneling in quantum antidots and to the Fabry-Perot oscillations. Using KPFM, to probe the charge carriers, and graphene-based structures to control valley transport, provides an efficient way for attaining valley filtering without involving external or pseudo-magnetic fields as in previous proposals.

Emergent non-Hermitian models. (arXiv:2310.11988v1 [quant-ph])
Lumen Eek, Anouar Moustaj, Malte Röntgen, Vincent Pagneux, Vassos Achilleos, Cristiane Morais Smith

The Hatano-Nelson and the non-Hermitian Su-Schrieffer-Heeger model are paradigmatic examples of non-Hermitian systems that host non-trivial boundary phenomena. In this work, we use recently developed graph-theoretical tools to design systems whose isospectral reduction -- akin to an effective Hamiltonian -- has the form of either of these two models. In the reduced version, the couplings and on-site potentials become energy-dependent. We show that this leads to interesting phenomena such as an energy-dependent non-Hermitian skin effect, where eigenstates can simultaneously localize on either ends of the systems, with different localization lengths. Moreover, we predict the existence of various topological edge states, pinned at non-zero energies, with different exponential envelopes, depending on their energy. Overall, our work sheds new light on the nature of topological phases and the non-Hermitian skin effect in one-dimensional systems.

Topological states of multiband superconductors with interband pairing. (arXiv:2310.12002v1 [cond-mat.supr-con])
M. F. Holst, M. Sigrist, K. V. Samokhin

We study the effects of interband pairing in two-band s-wave and d-wave superconductors with D4h symmetry in both time-reversal invariant as well as time-reversal symmetry breaking states. The presence of interband pairing qualitatively changes the nodal structure of the superconductor: nodes can (dis)appear, merge, and leave high-symmetry locations when interband pairing is tuned. Furthermore, in the d-wave case, we find that also the boundary modes change qualitatively when interband pairing increases: flat zero-energy Andreev bound states gap out and transition to helical edge states.

A soft departure from jamming: the compaction of deformable granular matter under high pressures. (arXiv:2310.12009v1 [cond-mat.soft])
Joel T. Clemmer, Joseph M. Monti, Jeremy B. Lechman

The high-pressure compaction of three dimensional granular packings is simulated using a bonded particle model (BPM) to capture linear elastic deformation. In the model, grains are represented by a collection of point particles connected by bonds. A simple multibody interaction is introduced to control Poisson's ratio and the arrangement of particles on the surface of a grain is varied to model both high- and low-frictional grains. At low pressures, the growth in packing fraction and coordination number follow the expected behavior near jamming and exhibit friction dependence. As the pressure increases, deviations from the low-pressure power-law scaling emerge after the packing fraction grows by approximately 0.1 and results from simulations with different friction coefficients converge. These results are compared to predictions from traditional discrete element method simulations which, depending on the definition of packing fraction and coordination number, may only differ by a factor of two. As grains deform under compaction, the average volumetric strain and asphericity, a measure of the change in the shape of grains, are found to grow as power laws and depend heavily on the Poisson's ratio of the constituent solid. Larger Poisson's ratios are associated with less volumetric strain and more asphericity and the apparent power-law exponent of the asphericity may vary. The elastic properties of the packed grains are also calculated as a function of packing fraction. In particular, we find the Poisson's ratio near jamming is 1/2 but decreases to 1/4 before rising again as systems densify.

Exploiting memory effects to detect the boundaries of biochemical subnetworks. (arXiv:2310.12022v1 [])
Moshir Harsh, Leonhard Götz Vulpius, Peter Sollich

Partial measurements of biochemical reaction networks are ubiquitous and limit our ability to reconstruct the topology of the reaction network and the strength of the interactions amongst both the observed and the unobserved molecular species. Here, we show how we can utilize noisy time series of such partially observed networks to determine which species of the observed part form its boundary, i.e. have significant interactions with the unobserved part. This opens a route to reliable network reconstruction. The method exploits the memory terms arising from projecting the dynamics of the entire network onto the observed subnetwork. We apply it to the dynamics of the Epidermal Growth Factor Receptor (EGFR) network and show that it works even for substantial noise levels.

Tuning the supercurrent distribution in parallel ballistic graphene Josephson junctions. (arXiv:2310.12040v1 [cond-mat.mes-hall])
Philipp Schmidt, Luca Banszerus, Benedikt Frohn, Stefan Blien, Kenji Watanabe, Takashi Taniguchi, Andreas K. Hüttel, Bernd Beschoten, Fabian Hassler, Christoph Stampfer

We report on a ballistic and fully tunable Josephson junction system consisting of two parallel ribbons of graphene in contact with superconducting MoRe. By electrostatic gating of the two individual graphene ribbons we gain control over the real space distribution of the superconducting current density, which can be continuously tuned between both ribbons. We extract the respective gate dependent spatial distributions of the real space current density by employing Fourier- and Hilbert transformations of the magnetic field induced modulation of the critical current. This approach is fast and does not rely on a symmetric current profile. It is therefore a universally applicable tool, potentially useful for carefully adjusting Josephson junctions.

Two-Dimensional Noble Metal Chalcogenides in the Frustrated Snub-Square Lattice. (arXiv:2310.12048v1 [cond-mat.mtrl-sci])
Hai-Chen Wang, Ahmad W. Huran, Miguel A. L. Marques, Muralidhar Nalabothula, Ludger Wirtz, Zachary Romestan, Aldo H. Romero

We study two-dimensional noble metal chalcogenides, with composition {Cu, Ag, Au}2{S, Se, Te}, crystallizing in a snub-square lattice. This is a semi-regular two-dimensional tesselation formed by triangles and squares that exhibits geometrical frustration. We use for comparison a square lattice, from which the snub-square tiling can be derived by a simple rotation of the squares. The mono-layer snub-square chalcogenides are very close to thermodynamic stability, with the most stable system (Ag2Se) a mere 7 meV/atom above the convex hull of stability. All compounds studied in the square and snub-square lattice are semiconductors, with band gaps ranging from 0.1 to more than 2.5 eV. Excitonic effects are strong, with an exciton binding energy of around 0.3 eV. We propose the Cu (001) surface as a possible substrate to synthesize Cu2Se, although many other metal and semiconducting surfaces can be found with very good lattice matching.

Large Rashba splittings in bulk and monolayer of BiAs. (arXiv:2310.12094v1 [cond-mat.mtrl-sci])
Muhammad Zubair, Igor Evangelista, Shoaib Khalid, Bharat Medasani, Anderson Janotti

Two-dimensional materials with Rashba split bands near the Fermi level are key to developing upcoming next-generation spintronics. They enable generating, detecting, and manipulating spin currents without an external magnetic field. Here, we propose BiAs as a novel layered semiconductor with large Rashba splitting in bulk and monolayer forms. Using first-principles calculations, we determined the lowest energy structure of BiAs and its basic electronic properties. Bulk BiAs has a layered crystal structure with two atoms in a rhombohedral primitive cell, similar to the parent Bi and As elemental phases. It is a semiconductor with a narrow and indirect band gap. The spin-orbit coupling leads to Rashba-Dresselhaus spin splitting and characteristic spin texture around the L-point in the Brillouin zone of the hexagonal conventional unit cell, with Rashba energy and Rashba coupling constant for valence (conduction) band of $E_R$= 137 meV (93 meV) and $\alpha_R$= 6.05 eV\AA~(4.6 eV{\AA}). In monolayer form (i.e., composed of a BiAs bilayer), BiAs has a much larger and direct band gap at $\Gamma$, with a circular spin texture characteristic of a pure Rashba effect. The Rashba energy $E_R$= 18 meV and Rashba coupling constant $\alpha_R$= 1.67 eV{\AA} of monolayer BiAs are quite large compared to other known 2D materials, and these values are shown to increase under tensile biaxial strain.

Spontaneous superconducting diode effect in non-magnetic Nb/Ru/Sr$_2$RuO$_4$ topological junctions. (arXiv:2211.14626v2 [cond-mat.supr-con] UPDATED)
M. S. Anwar, T. Nakamura, R. Ishiguro, S. Arif, J. W. A. Robinson, S. Yonezawa, M. Sigrist, Y. Maeno

Non-reciprocal electronic transport in a material occurs if both time reversal and inversion symmetries are broken. The superconducting diode effect (SDE) is an exotic manifestation of this type of behavior where the critical current for positive and negative currents are mismatched, as recently observed in some non-centrosymmetric superconductors with a magnetic field. Here, we demonstrate a SDE in non-magnetic Nb/Ru/Sr$_2$RuO$_4$ Josephson junctions without applying an external magnetic field. The cooling history dependence of the SDE suggests that time-reversal symmetry is intrinsically broken by the superconducting phase of Sr$_2$RuO$_4$. Applied magnetic fields modify the SDE dynamically by randomly changing the sign of the non-reciprocity. We propose a model for such a topological junction with a conventional superconductor surrounded by a chiral superconductor with broken time reversal symmetry.

Spatiotemporal control of active topological defects. (arXiv:2212.00666v2 [cond-mat.soft] UPDATED)
Suraj Shankar, Luca V. D. Scharrer, Mark J. Bowick, M. Cristina Marchetti

Topological defects play a central role in the physics of many materials, including magnets, superconductors and liquid crystals. In active fluids, defects become autonomous particles that spontaneously propel from internal active stresses and drive chaotic flows stirring the fluid. The intimate connection between defect textures and active flow suggests that properties of active materials can be engineered by controlling defects, but design principles for their spatiotemporal control remain elusive. Here we provide a symmetry-based additive strategy for using elementary activity patterns, as active topological tweezers, to create, move and braid such defects. By combining theory and simulations, we demonstrate how, at the collective level, spatial activity gradients act like electric fields which, when strong enough, induce an inverted topological polarization of defects, akin to an exotic negative susceptibility dielectric. We harness this feature in a dynamic setting to collectively pattern and transport interacting active defects. Our work establishes an additive framework to sculpt flows and manipulate active defects in both space and time, paving the way to design programmable active and living materials for transport, memory and logic.

Phonon Self-Energy Corrections: To Screen, or Not to Screen. (arXiv:2212.11806v3 [cond-mat.mtrl-sci] UPDATED)
Jan Berges, Nina Girotto, Tim Wehling, Nicola Marzari, Samuel Poncé

First-principles calculations of phonons are often based on the adiabatic approximation and on Brillouin-zone samplings that might not always be sufficient to capture the subtleties of Kohn anomalies. These shortcomings can be addressed through corrections to the phonon self-energy arising from the low-energy electrons. The exact self-energy involves a product of a bare and a screened electron-phonon vertex [Rev. Mod. Phys. 89, 015003 (2017)]; still, calculations often employ two adiabatically screened vertices, which have been proposed as a reliable approximation for self-energy differences [Phys. Rev. B 82, 165111 (2010)]. We assess the accuracy of both approaches in estimating the phonon spectral functions of model Hamiltonians and the adiabatic low-temperature phonon dispersions of monolayer TaS$_2$ and doped MoS$_2$. We find that the approximate method yields excellent corrections at low computational cost, due to its designed error cancellation to first order, while using a bare vertex could in principle improve these results but is challenging in practice. We offer an alternative strategy based on downfolding to partially screened phonons and interactions [Phys. Rev. B 92, 245108 (2015)]. This is a natural scheme to include electron-electron interactions and tackle phonons in strongly correlated materials and the frequency dependence of the electron-phonon vertex.

Singlet, Triplet and Pair Density Wave Superconductivity in the Doped Triangular-Lattice Moir\'e System. (arXiv:2302.06765v3 [cond-mat.str-el] UPDATED)
Feng Chen, D. N. Sheng

Recent experimental progress has established the twisted bilayer transition metal dichalcogenide (TMD) as a highly tunable platform for studying many-body physics. Particularly, the homobilayer TMDs under displacement field are believed to be described by a generalized triangular-lattice Hubbard model with a spin-dependent hopping phase $\theta$. To explore the effects of $\theta$ on the system, we perform density matrix renormalization group calculations for the relevant triangular lattice t-J model. By changing $\theta$ at small hole doping, we obtain a region of quasi-long-range superconducting order coexisting with charge and spin density wave within $0<\theta<\pi/3$. The superconductivity is composed of a dominant spin singlet $d$-wave and a subdominant triplet $p$-wave pairing. Intriguingly, the $S_z=\pm 1$ triplet pairing components feature pair density waves. In addition, we find a region of triplet superconductivity coexisting with charge density wave and ferromagnetism within $\pi/3<\theta<2\pi/3$, which is related to the former phase at smaller $\theta$ by a combined operation of spin-flip and gauge transformation. Our findings provide insights and directions for experimental search for exotic superconductivity in twisted TMD systems.

Computing the Mass Shift of Wilson and Staggered Fermions in the Lattice Schwinger Model with Matrix Product States. (arXiv:2303.11016v2 [hep-lat] UPDATED)
Takis Angelides, Lena Funcke, Karl Jansen, Stefan Kühn

Simulations of lattice gauge theories with tensor networks and quantum computing have so far mainly focused on staggered fermions. In this paper, we use matrix product states to study Wilson fermions in the Hamiltonian formulation and present a novel method to determine the additive mass renormalization. Focusing on the single-flavor Schwinger model as a benchmark model, we investigate the regime of a nonvanishing topological $\theta$-term, which is inaccessible to conventional Monte Carlo methods. We systematically explore the dependence of the mass shift on the volume, the lattice spacing, the $\theta$-parameter, and the Wilson parameter. This allows us to follow lines of constant renormalized mass, and therefore to substantially improve the continuum extrapolation of the mass gap and the electric field density. For small values of the mass, our continuum results agree with the theoretical prediction from mass perturbation theory. Going beyond Wilson fermions, our technique can also be applied to staggered fermions, and we demonstrate that the results of our approach agree with a recent theoretical prediction for the mass shift at sufficiently large volumes.

A baby--Skyrme model with anisotropic DM interaction: Compact skyrmions revisited. (arXiv:2303.15751v4 [hep-th] UPDATED)
Funa Hanada, Nobuyuki Sawado

We consider a baby--Skyrme model with Dzyaloshinskii--Moriya interaction (DMI) and two types of potential terms. The model has a close connection with the vacuum functional of fermions coupled with $O(3)$ nonlinear $\bm{n}$-fields and with a constant $SU(2)$ gauge background. The energy functional is derived from the heat-kernel expansion for the fermion determinant. The model possesses normal skyrmions with topological charge $Q = 1$. The restricted version of the model also includes both the weak-compacton case (at the boundary, not continuously differentiable) and genuine-compacton case (continuously differentiable). The model consists of only the Skyrme term, and the DMI provides soliton solutions that are known as \textit{skyrmions without any potential}. The BPS equation in the supersymmetric soliton models implies that the impurity coupling is closely related to the DMI. Therefore, the effect of an exponentially localized DMI is also studied in the present model.

Interplay Between Magnetic Frustration and Quantum Criticality in the Unconventional Ladder Antiferromagnet C9H18N2CuBr4. (arXiv:2306.06021v2 [cond-mat.str-el] UPDATED)
Tao Hong, Imam Makhfudz, Xianglin Ke, Andrey A. Podlesnyak, Daniel Pajerowski, Barry Winn, Merce Deumal, Mark M. Turnbull

Quantum fluctuation in frustrated magnets and quantum criticality at the transition between different quantum phases of matter are two thrilling subjects in condensed matter physics. Here we demonstrate the nontrivial interplay between them in the spin-1/2 coupled two-leg ladder antiferromagnet C9H18N2CuBr4 (DLCB for short). Employing high-resolution neutron spectroscopy, we unambiguously identify a weakly first-order hydrostatic pressure-driven quantum phase transition, which arises from fluctuations enhanced by the frustrating interlayer coupling. An exotic pressure-induced quantum disordered state is evidenced by the broad spectral linewidth observed near the phase transition. We also find that the temperature dependence of the gapped transverse excitations in the Neel-ordered phase at ambient pressure cannot be described by the conventional S=1 magnons, i.e., the spin wave quanta, associated with explicit symmetry breaking. Instead, the thermal renormalization of the gap energies at ambient pressure shows a remarkable agreement with the theoretical calculation for the three-dimensional (3D) O(3) nonlinear-sigma model, which indicates that the ground state at ambient pressure is best described as a disordered singlet with a spin gap. Accordingly, the origin of the spin gap in DLCB is not owing to the spin anisotropy and the 3D magnetic order ought to emerge in an unconventional way. Haldane's conjecture on spin-1 chains is proposed to explain the opening of the spin gap in DLCB and the analysis of the free energy supports that the magnetic order of DLCB can arise exclusively from thermal fluctuations by order-by-disorder. Our results indicate the presence of a symmetry-protected topological phase at ambient pressure in this material.

Thermodynamics of interacting systems: the role of the topology and collective effects. (arXiv:2308.02255v2 [cond-mat.stat-mech] UPDATED)
Iago N. Mamede, Karel Proesmans, Carlos E. Fiore

We will study a class of system composed of interacting unicyclic machines placed in contact with a hot and cold thermal baths subjected to a non-conservative driving worksource. Despite their simplicity, these models showcase an intricate array of phenomena, including pump and heat engine regimes as well as a discontinuous phase transition. We will look at three distinctive topologies: a minimal and beyond minimal (homogeneous and heterogeneous interaction structures). The former case is represented by stark different networks ("all-to-all" interactions and only a central interacting to its neighbors) and present exact solutions, whereas homogeneous and heterogeneous structures have been analyzed by numerical simulations. We find that the topology plays a major role on the thermodynamic performance for smaller values of individual energies, in part due to the presence of first-order phase-transitions.Contrariwise, the topology becomes less important as individual energies increases and results are well-described by a system with all-to-all interactions.

Magnetized Baryonic layer and a novel BPS bound in the gauged-Non-Linear-Sigma-Model-Maxwell theory in (3+1)-dimensions through Hamilton-Jacobi equation. (arXiv:2309.03153v3 [hep-th] UPDATED)
Fabrizio Canfora

It is show that one can derive a novel BPS bound for the gauged Non-Linear-Sigma-Model (NLSM) Maxwell theory in (3+1) dimensions which can actually be saturated. Such novel bound is constructed using Hamilton-Jacobi equation from classical mechanics. The configurations saturating the bound represent Hadronic layers possessing both Baryonic charge and magnetic flux. However, unlike what happens in the more common situations, the topological charge which appears naturally in the BPS bound is a non-linear function of the Baryonic charge. This BPS bound can be saturated when the surface area of the layer is quantized. The far-reaching implications of these results are discussed. In particular, we determine the exact relation between the magnetic flux and the Baryonic charge as well as the critical value of the Baryonic chemical potential beyond which these configurations become thermodynamically unstable.

MOFDiff: Coarse-grained Diffusion for Metal-Organic Framework Design. (arXiv:2310.10732v1 [physics.chem-ph] CROSS LISTED)
Xiang Fu, Tian Xie, Andrew S. Rosen, Tommi Jaakkola, Jake Smith

Metal-organic frameworks (MOFs) are of immense interest in applications such as gas storage and carbon capture due to their exceptional porosity and tunable chemistry. Their modular nature has enabled the use of template-based methods to generate hypothetical MOFs by combining molecular building blocks in accordance with known network topologies. However, the ability of these methods to identify top-performing MOFs is often hindered by the limited diversity of the resulting chemical space. In this work, we propose MOFDiff: a coarse-grained (CG) diffusion model that generates CG MOF structures through a denoising diffusion process over the coordinates and identities of the building blocks. The all-atom MOF structure is then determined through a novel assembly algorithm. Equivariant graph neural networks are used for the diffusion model to respect the permutational and roto-translational symmetries. We comprehensively evaluate our model's capability to generate valid and novel MOF structures and its effectiveness in designing outstanding MOF materials for carbon capture applications with molecular simulations.

Found 9 papers in prb
Date of feed: Thu, 19 Oct 2023 03:17:11 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)

Quantum spin liquids on the diamond lattice
Aishwarya Chauhan, Atanu Maity, Chunxiao Liu, Jonas Sonnenschein, Francesco Ferrari, and Yasir Iqbal
Author(s): Aishwarya Chauhan, Atanu Maity, Chunxiao Liu, Jonas Sonnenschein, Francesco Ferrari, and Yasir Iqbal

The diamond lattice has been a promising playground for both classical and quantum spin liquids. Here, the authors conduct a comprehensive symmetry classification of S=½ quantum spin liquids with SU(2), U(1), and ℤ2 gauge fields, and present dynamical spin structure factors within a self-consistent simulation. The authors highlight three discoveries: spinon Ansätze with robust gapless nodal loops, topological bands realizing topological insulators, and that Gutzwiller projection of the 0- and π-flux SU(2) spin liquids generates long-range Néel order.

[Phys. Rev. B 108, 134424] Published Wed Oct 18, 2023

Superconductivity and magnetism in the surface states of ABC-stacked multilayer graphene
Oladunjoye A. Awoga, Tomas Löthman, and Annica M. Black-Schaffer
Author(s): Oladunjoye A. Awoga, Tomas Löthman, and Annica M. Black-Schaffer

ABC-stacked multilayer graphene (ABC-MLG) exhibits topological surface flat bands with a divergent density of states, leading to many-body instabilities at charge neutrality. Here, we explore electronic ordering within a mean-field approach with full generic treatment of all spin-isotropic, two-site…

[Phys. Rev. B 108, 144504] Published Wed Oct 18, 2023

Quantum Hall bilayer in dipole representation
S. Predin and M. V. Milovanović
Author(s): S. Predin and M. V. Milovanović

The Quantum Hall Bilayers (QHB) at filling factor $ν=1$ represents a competition between Bose-Einstein condensation (BEC) at small distances between layers and fermionic condensation, whose influence grows with distance and results in two separate Fermi liquid states for the underlying quasiparticle…

[Phys. Rev. B 108, 155129] Published Wed Oct 18, 2023

Laser-induced surface magnetization in Floquet-Weyl semimetals
Runnan Zhang, Ken-ichi Hino, Nobuya Maeshima, Haruki Yogemura, and Takeru Karikomi
Author(s): Runnan Zhang, Ken-ichi Hino, Nobuya Maeshima, Haruki Yogemura, and Takeru Karikomi

We investigate optically induced magnetization in Floquet-Weyl semimetals generated by irradiation of a circularly polarized continuous-wave laser from the group II-V narrow gap semiconductor ${\mathrm{Zn}}_{3}{\mathrm{As}}_{2}$ in a theoretical manner. Here, this trivial and nonmagnetic crystal is …

[Phys. Rev. B 108, 155308] Published Wed Oct 18, 2023

Shift photoconductivity in the Haldane model
Javier Sivianes and Julen Ibañez-Azpiroz
Author(s): Javier Sivianes and Julen Ibañez-Azpiroz

The shift current is part of the second-order optical response of materials with a close connection to topology. Here we report a sign inversion in the band-edge shift photoconductivity of the Haldane model when the system undergoes a topological phase transition. This result is obtained following t…

[Phys. Rev. B 108, 155419] Published Wed Oct 18, 2023

Partially topological phase in a quantum loop gas model with tension and pressure
J. Abouie and M. H. Zarei
Author(s): J. Abouie and M. H. Zarei

Enhancing robustness of topological orders against perturbations is one of the main goals in topological quantum computing. Since the kinetic of excitations is in conflict with the robustness of topological orders, any mechanism that reduces the mobility of excitations will be in favor of robustness…

[Phys. Rev. B 108, 165133] Published Wed Oct 18, 2023

Long-range Ising spins models emerging from frustrated Josephson junctions arrays with topological constraints
Oliver Neyenhuys, Mikhail V. Fistul, and Ilya M. Eremin
Author(s): Oliver Neyenhuys, Mikhail V. Fistul, and Ilya M. Eremin

Geometrical frustration in correlated systems can give rise to a plethora of ordered states and intriguing phases. Here, we theoretically analyze vertex-sharing frustrated Kagome lattices of Josephson junctions and identify various classical and quantum phases. The frustration is provided by periodi…

[Phys. Rev. B 108, 165413] Published Wed Oct 18, 2023

Electronic and magnetic properties of single chalcogen vacancies in ${\mathrm{MoS}}_{2}/\mathrm{Au}(111)$
Sergey Trishin, Christian Lotze, Nils Krane, and Katharina J. Franke
Author(s): Sergey Trishin, Christian Lotze, Nils Krane, and Katharina J. Franke

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) are considered highly promising platforms for next-generation optoelectronic devices. Owing to its atomically thin structure, device performance is strongly impacted by a minute amount of defects. Although defects are usually considered t…

[Phys. Rev. B 108, 165414] Published Wed Oct 18, 2023

Scale-free localization and $\mathcal{PT}$ symmetry breaking from local non-Hermiticity
Bo Li, He-Ran Wang, Fei Song, and Zhong Wang
Author(s): Bo Li, He-Ran Wang, Fei Song, and Zhong Wang

We show that a local non-Hermitian perturbation in a Hermitian lattice system generically induces scale-free localization for the continuous-spectrum eigenstates. When the perturbation lies at a finite distance to the boundary, the scale-free eigenstates are promoted to exponentially localized modes…

[Phys. Rev. B 108, L161409] Published Wed Oct 18, 2023

Found 6 papers in prl
Date of feed: Thu, 19 Oct 2023 03:17:09 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)

Entangling Dynamics from Effective Rotor–Spin-Wave Separation in U(1)-Symmetric Quantum Spin Models
Tommaso Roscilde, Tommaso Comparin, and Fabio Mezzacapo
Author(s): Tommaso Roscilde, Tommaso Comparin, and Fabio Mezzacapo

The nonequilibrium dynamics of quantum spin models is a most challenging topic, due to the exponentiality of Hilbert space, and it is central to the understanding of the many-body entangled states that can be generated by state-of-the-art quantum simulators. A particularly important class of evoluti…

[Phys. Rev. Lett. 131, 160403] Published Wed Oct 18, 2023

Shadow Tomography from Emergent State Designs in Analog Quantum Simulators
Max McGinley and Michele Fava
Author(s): Max McGinley and Michele Fava

We introduce a method that allows one to infer many properties of a quantum state—including nonlinear functions such as Rényi entropies—using only global control over the constituent degrees of freedom. In this protocol, the state of interest is first entangled with a set of ancillas under a fixed g…

[Phys. Rev. Lett. 131, 160601] Published Wed Oct 18, 2023

Microscopic Encoding of Macroscopic Universality: Scaling Properties of Dirac Eigenspectra near QCD Chiral Phase Transition
H.-T. Ding, W.-P. Huang, Swagato Mukherjee, and P. Petreczky
Author(s): H.-T. Ding, W.-P. Huang, Swagato Mukherjee, and P. Petreczky

Macroscopic properties of the strong interaction near its chiral phase transition exhibit scaling behaviors, which are the same as those observed close to the magnetic transition in a three-dimensional classical spin system with O(4) symmetry. We show that the universal scaling properties of the chi…

[Phys. Rev. Lett. 131, 161903] Published Wed Oct 18, 2023

Strain-Induced Quasi-1D Channels in Twisted Moiré Lattices
Andreas Sinner, Pierre A. Pantaleón, and Francisco Guinea
Author(s): Andreas Sinner, Pierre A. Pantaleón, and Francisco Guinea

We study the effects of strain in moiré systems composed of honeycomb lattices. We elucidate the formation of almost perfect one-dimensional moiré patterns in twisted bilayer systems. The formation of such patterns is a consequence of an interplay between twist and strain which gives rise to a colla…

[Phys. Rev. Lett. 131, 166402] Published Wed Oct 18, 2023

Hopfion-Driven Magnonic Hall Effect and Magnonic Focusing
Carlos Saji, Roberto E. Troncoso, Vagson L. Carvalho-Santos, Dora Altbir, and Alvaro S. Nunez
Author(s): Carlos Saji, Roberto E. Troncoso, Vagson L. Carvalho-Santos, Dora Altbir, and Alvaro S. Nunez

Hopfions are localized and topologically nontrivial magnetic configurations that have received considerable attention in recent years. In this Letter, we use a micromagnetic approach to analyze the scattering of spin waves (SWs) by magnetic hopfions. Our results evidence that SWs experience an elect…

[Phys. Rev. Lett. 131, 166702] Published Wed Oct 18, 2023

Unraveling the Oxidation of a Graphitic Lattice: Structure Determination of Oxygen Clusters
Mohammad Tohidi Vahdat, Shaoxian Li, Shiqi Huang, Carlo A. Pignedoli, Nicola Marzari, and Kumar Varoon Agrawal
Author(s): Mohammad Tohidi Vahdat, Shaoxian Li, Shiqi Huang, Carlo A. Pignedoli, Nicola Marzari, and Kumar Varoon Agrawal

Unraveling the oxidation of graphitic lattice is of great interest for atomic-scale lattice manipulation. Herein, we build epoxy cluster, atom by atom, using Van der Waals’ density-functional theory aided by Clar’s aromatic π-sextet rule. We predict the formation of cyclic epoxy trimers and its line…

[Phys. Rev. Lett. 131, 168001] Published Wed Oct 18, 2023

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]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Anisotropic resistance with a 90° twist in a ferromagnetic Weyl semimetal, Co2MnGa
< author missing >

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)

General construction scheme for geometrically nontrivial flat band models
Jun-Won Rhim

Communications Physics, Published online: 18 October 2023; doi:10.1038/s42005-023-01407-6

The quantum distance quantifies the similarity between two quantum states and plays a relevant role in the physics of flat bands, e.g. flat band superconductivity or Landau levels. The authors propose a construction scheme for tight-binding models hosting a singular flat band with a prescribed maximum quantum distance and establish a bulk-boundary correspondence between the quantum distance and the boundary modes.

Found 1 papers in scipost

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Topological Defect Lines in Two Dimensional Fermionic CFTs, by Chi-Ming Chang, Jin Chen, Fengjun Xu
< author missing >
Submitted on 2023-10-18, refereeing deadline 2023-11-23.