Extended states and dynamical localization in the random-dimer model

TL;DR

This paper investigates how an electric field affects quantum diffusion in one-dimensional random binary lattices, revealing that delocalized states in random dimer lattices become localized but still less so than in purely random lattices.

Contribution

It demonstrates the impact of electric fields on dynamical localization in random dimer models, highlighting the persistence of resonant tunneling effects.

Findings

Delocalized states in random dimer lattices become localized under electric field.

Wavepackets in dimer lattices are less localized than in random lattices.

Resonant tunneling influences localization even with an applied electric field.

Abstract

We study quantum diffusion of wavepackets in one-dimensional random binary subject to an applied electric field. We consider three different cases: Periodic, random, and random dimer (paired) lattices. We analyze the spatial extent of electronic wavepackets by means of the time-dependent inverse participatio ratio. We show that the delocalized states recently found in random dimer lattices become spatially localized under the action of the applied field (dynamical localization) but wavepackets are much less localized than in purely random lattices. We conclude that the resonant tunneling effects causing delocalization play an important role even in the presence of the electric field.