{
  "id": "1805.10866",
  "version": "v1",
  "published": "2018-05-28T11:16:45.000Z",
  "updated": "2018-05-28T11:16:45.000Z",
  "title": "Floquet states of $ α$-$T_3$ lattice: Role of variable Berry phase",
  "authors": [
    "Bashab Dey",
    "Tarun Kanti Ghosh"
  ],
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "We consider $\\alpha$-$T_3$ model 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 $\\alpha$-$T_3$ model by solving the Floquet Hamiltonian. We obtain exact analytical expressions of the quasienergies at the Dirac points for all values of $\\alpha$ and field strength. We find that the quasienergy band gaps at the Dirac point decrease with increase of $\\alpha$. 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 unchanged in presence of radiation for dice lattice. However, it acquires a dispersion in and around the Dirac and even-photon resonant points when $0<\\alpha<1$. The valley degeneracy and electron-hole symmetry in the quasienergy spectrum are also broken for $0<\\alpha<1$. Unlike graphene, the mean energy follows closely the linear dispersion of Dirac cones till near the two-photon resonant points. There are additional peaks in the time-averaged density of states at the Dirac point for $0<\\alpha \\leq 1$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-05-28T11:16:45.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "variable berry phase",
      "floquet states",
      "dirac point",
      "resonant points",
      "quasi energy flat band remains"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}