title: Topological Valley Currents in Gapped Dirac Materials.
abstract: Gapped 2D Dirac materials, in which inversion symmetry is broken by a gap-opening perturbation, feature a unique valley transport regime. Topological valley currents in such materials are dominated by bulk currents produced by electronic states just beneath the gap rather than by edge modes. The system ground state hosts dissipationless persistent valley currents existing even when topologically protected edge modes are absent. Valley currents induced by an external bias are characterized by a quantized half-integer valley Hall conductivity. The undergap currents dominate magnetization and the charge Hall effect in a light-induced valley-polarized state.
authors.affiliation: Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Yuri D
authors.initials: YD
authors.lastname: Lensky
authors.affiliation: Walter Burke Institute for Theoretical Physics and Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Justin C W
authors.initials: JC
authors.lastname: Song
authors.affiliation: Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Polnop
authors.initials: P
authors.lastname: Samutpraphoot
authors.affiliation: Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Leonid S
authors.initials: LS
authors.lastname: Levitov