Related papers: Ultrafast topological phenomena in gapped graphene
We theoretically study the electronic structure of small-angle twisted bilayer graphene with a large potential asymmetry between the top and bottom layers. We show that the emergent helical states known to appear on the triangular AB-BA…
We uncover topological features of neutral particle-hole pair excitations of correlated quantum anomalous Hall (QAH) insulators whose approximately flat conduction and valence bands have equal and opposite non-zero Chern number. Using an…
We study gap solitons which appear in the topological gap of 1D bosonic dimer chains within the mean-field approximation. We find that such solitons have a non-trivial texture of the sublattice pseudospin. We reveal their chiral nature by…
Intrinsic ripples in freestanding graphene have been exceedingly difficult to study. Individual ripple geometry was recently imaged using scanning tunneling microscopy, but these measurements are limited to static configurations.…
A class of graphene wound into three-dimensional periodic curved surfaces ("graphitic zeolites") is proposed and their electronic structures are obtained to explore how the massless Dirac fermions behave on periodic surfaces. We find in the…
Domains of finite topological charge density can exist in chiral materials and chiral matter. Spatial and temporal variation of the average topological charge density, represented by the $\theta$-field, induces anomalous currents that are…
Chiral edge modes in photonic topological insulators host great potential to realize slow-light waveguides with topological protection. Increasing the winding of the chiral edge mode around the Brillouin zone can lead to broadband…
We outline an approach to endow a plain vanilla material with topological properties by creating topological bands in stacks of manifestly nontopological atomically thin materials. The approach is illustrated with a model system comprised…
We investigate the effect of electron- $\mathrm{A}_{1g}$ phonon coupling on the gapless electronic band dispersion of the pristine graphene. The electron-phonon interaction is introduced through a Kekul\'{e}-type distortion giving rise to…
We propose a scheme to trap and filter electrons, valley dependently, on a scale beyond the diffraction limit, in a gapped Dirac system using a circularly polarized light beam and a microscale metallic resonator. The main mechanism allowing…
Hydrogen adsorption on graphene in commensurate periodic arrangements leads to bandgap opening at the Dirac point and the emergence of dispersionless midgap bands. We study these bandgap effects and their dependence on periodicity for a…
In periodic systems, band degeneracies are usually protected and classified by spatial symmetries. However, the Gamma point at zero-frequency of a photonic system is an intrinsic degeneracy due to the polarization degree of freedom of…
We develop the topological band theory for systems described by non-Hermitian Hamiltonians, whose energy spectra are generally complex. After generalizing the notion of gapped band structures to the non-Hermitian case, we classify "gapped"…
The topological properties of electronic edge states in time-periodically driven spatially-periodic corrugated zigzag graphene nanoribbons are studied. An effective one-dimensional Hamiltonian is used to describe the electronic properties…
Theory predicts that graphene under uniaxial compressive strain in an armchair direction should undergo a topological phase transition from a semimetal into an insulator. Due to the change of the hopping integrals under compression, both…
It is now well-established that photonic systems can exhibit topological energy bands; similar to their electronic counterparts, this leads to the formation of chiral edge modes which can be used to transmit light in a manner that is…
We study the topological phase transitions induced in spin-orbit coupled materials with buckling like silicene, germanene, stanene, etc, by circularly polarised light, beyond the high frequency regime, and unearth many new topological…
We study $d$-wave superconductivity in twisted bilayer graphene and reveal phenomena that arise due to the moir\'e superlattice. In the $d$-wave pairing, the relative motion (RM) of two electrons in a Cooper pair can have either $d+id$ or…
Based on the full Hamiltonian of bilayer graphene, phase transitions are realized by the change of the in-plane magnetic field and the electrical bias in bilayer graphene. We show that the engineering of Chern numbers of four bands is…
We predict novel topological phases with broken time-reversal symmetry supporting the coexistence of opposite chiral edge states, which are fundamentally different from the photonic spin-Hall, valley-Hall, and higher-order topological…