We investigate the properties of Lieb lattice, i.e a face-centered square subjected to external gauge fields. show that an Abelian field leads peculiar quantum Hall effect, which is consequence single Dirac cone and flat band characterizing energy spectrum. Then we explore effects intrinsic spin-orbit term - non-Abelian demonstrate occurrence spin effect in this model. Besides, obtain relativistic Hamiltonian describing lattice at low derive Landau levels presence Finally, describe concrete...

We propose an experimental setup for the observation of quasirelativistic massless fermions. It is based on a ${\mathcal{T}}_{3}$ optical lattice, realized by three pairs counterpropagating lasers, filled with fermionic cold atoms. show that in long wavelength approximation Hamiltonian generalizes Dirac-Weyl honeycomb however, larger value pseudospin $S=1$. In addition to Dirac cones, spectrum includes dispersionless branch localized states producing finite jump atomic density. Furthermore,...

We address the problem of barrier tunneling in two-dimensional T_3 lattice (dice lattice). In particular we focus on low-energy, long-wavelength approximation for Hamiltonian system, where can be described by a Dirac-like associated with pseudospin one. The enlarged S = 1 (instead 1/2 as graphene) leads to an enhanced "super" Klein through rectangular electrostatic barriers. Our results are confirmed via numerical investigation tight-binding model lattice. For uniform magnetic field, discuss...

Abstract The field of topological photonics emerged as one the most promising areas for applications in transformative technologies: possible are lasers or quantum optics interfaces. Nevertheless, efficient and simple methods diagnosing topology optical systems remain elusive an important part community. Herein, a summary numerical to calculate invariants emerging from propagation light photonic crystals is provided. fundamental properties wave lattices with space‐dependent periodic electric...

Topological photonic crystals are promising optical devices for long-distance communication and signal processing. In this work, the authors show how theory of band representations--developed finding topological electronic materials--can be used to design characterize these new crystal structures. As an example, paper proposes a structure that realizes first time in non-interacting system newly-introduced idea fragile topology.

We address the problem of spin-resolved scattering through spin-orbit nanostructures in graphene, i.e., regions inhomogeneous coupling on nanometer scale. discuss phenomenon spin-double refraction and its consequences spin polarization. Specifically, we study transmission properties a single double interface between normal region with finite coupling, analyze polarization these systems. Moreover, for case interface, determine spectrum edge states localized at boundary two their properties.

We analyze the robustness of corner modes in topological photonic crystals, taking a C6-symmetric breathing honeycomb crystal as an example. First, we employ quantum chemistry and Wilson loop calculations to demonstrate that properties bulk stem from obstructed atomic limit phase. then characterize emerging within gapped edge employing semianalytical model, determining appropriate real-space invariants. provide detailed account effect long-range interactions on quantify their perturbations....

We study the non-trivial phase of two-dimensional breathing kagome lattice, displaying both edge and corner modes. The localized modes a flake were initially identified as signature higher-order topological but later shown to be trivial for perturbations that thought protect them. Using various theoretical simulation techniques, we confirm it does not display topology: are nature. Nevertheless, they might protected. First, show set within tight-binding model can move away from zero energy,...

The chiral surface states of Weyl semimetals have an open Fermi called a arc. At the interface between two semimetals, these arcs are predicted to hybridize and alter their connectivity. In this Letter, we numerically study one-dimensional (1D) dielectric trilayer grating where relative displacements adjacent layers play role synthetic momenta. lattice emulates 3D crystals without time-reversal symmetry, including semimetal, nodal line Chern insulator. Besides showing phase transition...

We study the topological properties of a kagome plasmonic metasurface, modelled with coupled dipole method which naturally includes retarded long range interactions. demonstrate system supports an obstructed atomic limit phase through calculation Wilson loops. Then we characterise hierarchy boundary modes hosted by subwavelength array nanoparticles: both one-dimensional edge as well zero-dimensional corner modes. determine these robustly confine light at scales, calculate local density...

The hallmark of topological crystalline insulators is the emergence a robust electronic state in bandgap localized at boundary material. However, end, edge, and surface states can also have nontopological origin. Unfortunately, invariants such as winding number Zak phase are often not directly experimentally accessible for solids. In addition to invariants, position Wannier centers provides fingerprint character Here, we demonstrate method determine location artificial lattices made...

Physical phenomena driven by topological properties, such as the quantum Hall effect, have appealing feature that they are robust with respect to external perturbations. Lately, a new class of materials has emerged manifests properties at room temperature and without need magnetic fields. These insulators band large spin-orbit interactions exhibit spin-Hall (QSH) effect. Here we investigate transition between QSH normal insulating phases under deformations two-dimensional lattice. We...

We study a quantum network extending in one dimension (chain of square loops connected at vertex) made up wires with Rashba spin-orbit coupling. show that the effect may give rise to an electron localization phenomenon similar induced by magnetic field. This can be attributed spin precession due effect. present results both for spectral properties infinite chain and linear transport through finite-size leads. Furthermore, we disorder on this network.

We propose a device that allows for the emission of pairs spin-polarized electrons into edge states two-dimensional topological insulator. Charge and spin is achieved using periodically driven quantum dot weakly coupled to host present calculations emitted time-dependent charge currents such dynamical scatterer Floquet scattering matrix approach. Experimental signatures two-particle can be found in noise measurements. Here new form suppression, named ${\mathbb{Z}}_{2}$ antibunching,...

We present a formalism to study quantum networks made up by single-channel wires in the presence of Rashba spin-orbit coupling and magnetic field. In particular, linear transport through one-dimensional two-dimensional finite-size is studied means scattering formalism. some particular networks, action field or induces localization electron wave function. This phenomenon, which relies on both quantum-mechanical interference geometry network, manifested suppression conductance for specific...

The effect of Rashba spin–orbit interaction in quantum wires with hard-wall boundaries is discussed. exact wavefunction and eigenvalue equation are worked out, pointing out the mixing between spin spatial parts. spectral properties also studied within perturbation theory respect to strength diagonalization procedure. A comparison made results a simple model, two-band that takes account only first two sub-bands wire. Finally, transport ballistic regime analytically calculated for model...

Abstract The spectral properties of a non‐Hermitian quasi‐1D lattice in two the possible dimerization configurations are investigated. Specifically, it focuses on diamond chain that presents zero‐energy flat band. band originates from wave interference and results eigenstates with finite contribution only sites unit cell. To achieve characteristics, system under study non‐reciprocal hopping terms chain. This leads to accumulation boundary system, known as skin effect. Despite this...

We study a gated quantum wire contacted to source and drain electrodes in the Fabry-P\'erot regime. The is also coupled third terminal (tip), we allow for an asymmetry of tip tunneling amplitudes right-moving left-moving electrons. analyze configurations where acts as electron injector or voltage probe show that transport properties this three-terminal setup exhibit very rich physical behavior. For noninteracting find voltage-probe configuration affects source-drain different ways, namely,...

Superconducting proximity effects in graphene have received a great deal of attention for over decade now. This has unveiled plethora exotic linked to the specificities graphene's electronic properties. The vast majority related studies are based on conventional, low-temperature superconducting metals with isotropic $s$-wave pairing. Here we review recent advances made less studied case unconventional high-temperature cuprates. These characterized by an anisotropic $d$-wave pairing, whose...

Materials featuring touching points, localized states, and flat bands are of great interest in condensed matter artificial systems due to their implications topology, quantum geometry, superconductivity, interactions. In this theoretical study, we propose the experimental realization dice lattice with adjustable parameters by arranging carbon monoxide molecules on a two-dimensional electron system at (111) copper surface. First, develop framework obtain spectral properties within nearly free...

We demonstrate how the Rashba spin-orbit coupling in semiconductor heterostructures can produce and control a spin-polarized current without ferromagnetic leads. Key idea is to use spin-double refraction of an electronic beam with nonzero incidence angle. A region where present separates source drain coupling. show transmission spin-polarization critically depend on The halves when angle greater than limit significant appears. Increasing one obtain modulation intensity output input...

We predict the possibility to generate a finite stationary spin current by applying an unbiased ac driving quasi-one-dimensional asymmetric periodic structure with Rashba spin-orbit interaction and strong dissipation. show that under coupling strength between orbital degrees of freedom electron dynamics at low temperatures exhibits pure ratchet behavior, i.e., absence charge transport in spatially structures. It is also found equilibrium currents are not destroyed presence