Controlled population of 2D Floquet topological insulators


  Iliya Esin  ,  Mark S. Rudner  ,  Netanel H. Lindner  
Physics Department, Technion, 320003 Haifa, Israel
Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
Physics Department, Technion, 320003 Haifa, Israel

Periodically driven systems have been extensively studied as a promising platform for exploring new phases of quantum systems. In this work we study the steady states of 2D Floquet topological insulators. We consider a 2D system subjected to a time-periodic external drive, whose frequency is resonant with transitions from the valence to the conduction band. The Floquet-Bloch band-structure of the system is in a topological phase, akin to an equilibrium topological insulator. We consider the effects of radiative recombination and electron-phonon interactions. We show that the bulk exhibits a non-equilibrium steady state resembling two Fermi-Dirac distributions with separate chemical potentials for the electrons and holes, while the chiral Floquet edges exhibit an electronic distribution akin to an equilibrium Fermi function. Our results open future routes for probing the edge states of Floquet topological insulators.