Anderson localization in an ac-driven two-band model

The introduction of quasienergy bands for lattices interacting with combined ac and de fields allows us to describe the time evolution in close analogy to the field-free case. We show how such bands emerge for a two-band tight-binding model, and present analytical and numerical results for its quasienergy band structure. The ratio of disorder strength and quasienergy band width determines the localization lengths of the quasienergy states. Since the quasienergy band widths depend on the field parameters, this leads to a possibility of controlling Anderson localization by adjusting the ac amplitude. It is suggested that signatures of ac-field-controlled Anderson localization can be found by examining the temperature dependency of the conductivity of terahertz-driven semiconductor superlattices, for various values of the ac amplitude.