ac-Field-Controlled Anderson Localization in Disordered Semiconductor Superlattices

TL;DR

This paper investigates how an ac field resonant with the Stark ladder influences localization in disordered semiconductor superlattices, revealing non-monotonic localization length behavior and potential applications in material characterization.

Contribution

It demonstrates the control of Anderson localization via resonant ac fields in disordered superlattices, highlighting the non-monotonic dependence of localization lengths on field amplitude.

Findings

Resonant ac fields can delocalize states in ideal lattices under strong bias.

Disorder causes localization, which can be modulated by the ac field.

Localization lengths vary non-monotonically with ac field amplitude.

Abstract

An ac field, tuned exactly to resonance with the Stark ladder in an ideal tight binding lattice under strong dc bias, counteracts Wannier-Stark localization and leads to the emergence of extended Floquet states. If there is random disorder, these states localize. The localization lengths depend non-monotonically on the ac field amplitude and become essentially zero at certain parameters. This effect is of possible relevance for characterizing the quality of superlattice samples, and for performing experiments on Anderson localization in systems with well-defined disorder.