Extended states in disordered systems: role of off-diagonal correlations

TL;DR

This paper investigates how off-diagonal correlations in disordered one-dimensional systems can create extended states, with implications for charge transport in DNA and potential experimental verification in superlattices.

Contribution

It introduces a model showing off-diagonal correlations induce extended states at a specific correlation condition, advancing understanding of disorder effects in low-dimensional systems.

Findings

Effective conduction channels are generated by off-diagonal correlations.

An extended state exists at a golden correlation condition for infinite systems.

Proposes experimental setups in semiconductor superlattices to test predictions.

Abstract

We study one-dimensional systems with random diagonal disorder but off-diagonal short-range correlations imposed by structural constraints. We find that these correlations generate effective conduction channels for finite systems. At a certain golden correlation condition for the hopping amplitudes, we find an extended state for an infinite system. Our model has important implications to charge transport in DNA molecules, and a possible set of experiments in semiconductor superlattices is proposed to verify our most interesting theoretical predictions.