A Metal-Insulator transition induced by Random Dipoles

TL;DR

This paper investigates how the interplay of short-range and long-range correlations in a disordered dipolar potential affects localization, revealing a transition between localized and extended states.

Contribution

It demonstrates that long-range correlations can suppress extended states and alter localization lengths, providing new insights into disorder-induced localization phenomena.

Findings

Extended states appear with dominant short-range correlations.

Long-range correlations restore localization across the spectrum.

Long-range correlations modify localization lengths at the band center.

Abstract

We study the localization properties of a test dipole feeling the disordered potential induced by dipolar impurities trapped at random positions in an optical lattice. This random potential is marked by correlations which are a convolution of short-range and long-range ones. We show that when short-range correlations are dominant, extended states can appear in the spectrum. Introducing long-range correlations, the extended states, if any, are wiped out and localization is restored over the whole spectrum. Moreover, long-range correlations can either increase or decrease the localization length at the center of the band, which indicates a richer behavior than previously predicted.