title: Unconventional quantum Hall effect in Floquet topological insulators.
abstract: We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the light's polarization. We find a novel quantum Hall state in which the zeroth Landau level undergoes a phase transition from a trivial insulator state, with Hall conductivity [Formula: see text] at zero Fermi energy, to a Hall insulator state with [Formula: see text]. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at [Formula: see text].
authors.affiliation: Department of Physics, Concordia University, Montreal, QC H3G 1M8, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Tahir
authors.forename: P
authors.initials: P
authors.lastname: Vasilopoulos
authors.forename: U
authors.initials: U
authors.lastname: Schwingenschlögl