Locally Disordered Lattices in Strong ac Electric Fields

TL;DR

This paper introduces a formalism to analyze how local defects in tight binding lattices affect localized states under strong ac electric fields, with potential control via field parameters.

Contribution

It presents a new theoretical approach to control and understand defect-induced localized states in lattices subjected to strong ac fields.

Findings

Localized states can be created or destroyed by tuning the ac field amplitude or frequency.

Localization lengths of states are adjustable through external field parameters.

Numerical models demonstrate the theory's application to semiconductor superlattices.

Abstract

We develop a formalism to study the role of local defects in tight binding systems in the presence of a strong external ac electric field. It is found that the appearance and disappearance of localized states, as well as their localization lengths, can be controlled by the amplitude or frequency of the driving field. The theory is illustrated by numerical model calculations for imperfect semiconductor superlattices in far--infrared laser fields.