Experimental evidence of delocalized states in random dimer superlattices

TL;DR

This paper provides experimental evidence that spatial correlations in disordered superlattices can prevent localization of electronic states, challenging previous beliefs that all eigenstates are localized in such systems.

Contribution

It presents the first experimental demonstration that correlated disorder can inhibit localization in low-dimensional disordered systems, confirming earlier theoretical predictions.

Findings

Correlated disorder inhibits localization in superlattices.

Experimental evidence supports theoretical predictions.

Contrasts with earlier beliefs of universal localization.

Abstract

We study the electronic properties of GaAs-AlGaAs superlattices with intentional correlated disorder by means of photoluminescence and vertical dc resistance. The results are compared to those obtained in ordered and uncorrelated disordered superlattices. We report the first experimental evidence that spatial correlations inhibit localization of states in disordered low-dimensional systems, as our previous theoretical calculations suggested, in contrast to the earlier belief that all eigenstates are localized.