Floquet topological phases coupled to environments and the induced photocurrent

Szabolcs Vajna, Baruch Horovitz, Balázs Dóra, Gergely Zaránd

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12 Scopus citations

Abstract

We consider the fate of a helical edge state of a spin Hall insulator and its topological transition in presence of a circularly polarized light when coupled to various forms of environments. A Lindblad-type equation is developed to determine the fermion occupation of the Floquet bands. We find by using analytical and numerical methods that nonsecular terms, corresponding to two-photon transitions, lead to a mixing of the band occupations, hence the light-induced photocurrent is in general not perfectly quantized in the presence of finite coupling to the environment, although deviations are small in the adiabatic limit. Sharp crossovers are identified at driving frequencies near the Rabi frequency Ω (which is the strength of light-matter coupling) and at 12Ω with the former resembling a phase transition.

Original languageEnglish
Article number115145
JournalPhysical Review B
Volume94
Issue number11
DOIs
StatePublished - 21 Sep 2016

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