Photoinduced interfacial chiral modes in threefold topological semimetal

Islam, SK Firoz; Zyuzin, A. A.

doi:10.1103/physrevb.100.165302

Cited by 24 publications

(13 citation statements)

References 46 publications

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“…The two energy bands form a Dirac cone and the third band is completely flat and has zero energy [1,2]. Several physical quantities have been studied in the α − T 3 lattice such as orbital susceptibility [2], optical conductivity [9][10][11], and magnetotransport [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Electron states for gapped pseudospin-1 fermions in the field of a charged impurity

2019

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The electron states of gapped pseudospin-1 fermions of the α − T3 lattice in the Coulomb field of a charged impurity are studied. The free α − T3 model has three dispersive bands with two energy gaps between them depending on the parameter Θ which controls the coupling of atoms of honeycomb lattice with atoms in the center of each hexagon, thus, interpolating between graphene Θ = 0 and the dice model Θ = π/4. The middle band becomes flat one with zero energy in the dice model. The bound electron states are found in the two cases: the centrally symmetric potential well and a regularized Coulomb potential of the charged impurity. As the charge of impurity increases, bound state energy levels descend from the upper and central continua and dive at certain critical charges into the central and lower continuum, respectively. In the dice model, it is found that the flat band survives in the presence of a potential well, however, is absent in the case of the Coulomb potential. The analytical results are presented for the energy levels near continuum boundaries in the potential well. For the genuine Coulomb potential, we present the recursion relations that determine the coefficients of the series expansion of wave functions of bound states. It is shown that the condition for the termination of the series expansion gives two equations relating energy and charge values. Hence, analytical solutions can exist for a countably infinite set of values of impurity charge at fixed Θ.

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Section: Introductionmentioning

confidence: 99%

“…The Chern numbers as a function of the parameter Θ for m > 0. The density of states(15) for m = 1 and for angles Θ = π 10 , Θ = π 6 , Θ = π 3 .…”

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confidence: 99%

Electron states for gapped pseudospin-1 fermions in the field of a charged impurity

2019

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“…Recently, a list of physical quantities like orbital susceptibility 24 , optical conductivity 27,27,29 , magnetotransport properties 30,[32][33][34] , Klein tunneling 20,35 and wave-packet dynamics 36 in α-T 3 lattice have been studied extensively. The Berry phase has become indispensable ingredient in modern condensed matter physics due to its strong influence on magnetic, transport and optical properties 31 .…”

Section: Introductionmentioning

confidence: 99%

Photoinduced valley and electron-hole symmetry breaking in α−T3 lattice: The role of a variable Berry phase

Dey

Ghosh

2018

Phys. Rev. B

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We consider α-T3 lattice illuminated by intense circularly polarized radiation in terahertz regime. We present quasienergy band structure, time-averaged energy spectrum and time-averaged density of states of α-T3 lattice by solving the Floquet Hamiltonian numerically. We obtain exact analytical expressions of the quasienergies at the Dirac points for all values of α and field strength. We find that the quasienergy band gaps at the Dirac point decrease with increase of α. Approximate forms of quasienergy and band gaps at single and multi-photon resonant points are derived using rotating wave approximation. The expressions reveal a stark dependence of quasienergy on the Berry phase of the charge carrier. The quasi energy flat band remains unaltered in presence of radiation for dice lattice (α = 1). However, it acquires a dispersion in and around the Dirac and even-photon resonant points when 0 < α < 1. The valley degeneracy and electron-hole symmetry in the quasienergy spectrum are broken for 0 < α < 1. Unlike graphene, the mean energy follows closely the linear dispersion of the Dirac cones till near the single-photon resonant point in dice lattice. There are additional peaks in the time-averaged density of states at the Dirac point for 0 < α ≤ 1. arXiv:1805.10866v3 [cond-mat.mes-hall]

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“…Most of the attention has been devoted to illuminating two-dimensional materials, including graphene, 10,[34][35][36] germanene, 37 silicene, 38 and MoS2. 39 More recently, the interest in Floquet engineering three-dimensional materials such as three-dimensional topological insulators, 40,41 Weyl semimetals 42 or Dirac materials 43 has been growing.…”

Section: Introductionmentioning

confidence: 99%

Floquet boundary states in AB -stacked graphite

2020

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We report on the effect of laser illumination with circularly polarized light on the electronic structure of ABstacked graphite samples. By using Floquet theory in combination with Green's function techniques, we find that the polarized light induces bandgap openings at the Floquet zone edge Ω/2, bridged by chiral boundary states. These states propagate mainly along the borders of the constituting layers as evidenced from the timeaveraged local density of states and probability current density in several geometries. Semi-analytic calculations of the Chern number suggest that these states are of topological nature, similar to those found in illuminated 2D samples like monolayer and bilayer graphene. These states are promising candidates for the realization of a three-dimensional version of the quantum Hall effect for Floquet systems.

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Photoinduced interfacial chiral modes in threefold topological semimetal

Cited by 24 publications

References 46 publications

Electron states for gapped pseudospin-1 fermions in the field of a charged impurity

Electron states for gapped pseudospin-1 fermions in the field of a charged impurity

Photoinduced valley and electron-hole symmetry breaking in α−T3 lattice: The role of a variable Berry phase

Floquet boundary states in AB -stacked graphite

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