Anderson localization in Hubbard ladders

TL;DR

This paper studies how weak disorder causes Anderson localization in two-leg Hubbard ladders, suppressing superconductivity, with implications for related ladder compounds, and provides detailed conductivity and localization length results.

Contribution

It demonstrates that weak random potentials induce strong Anderson localization in Hubbard ladders, significantly affecting superconductivity and extending to coupled ladder systems.

Findings

Localization persists even with many coupled ladders

Superconductivity is suppressed by localization effects

Conductivities and localization lengths are quantitatively characterized

Abstract

The effect of a weak random potential on two-leg Hubbard ladders is investigated. The random potential is shown to induce Anderson localization except for attractive enough interactions, supressing completely d-wave superconductivity. These localization effects remain very strong even for many ladders coupled by Josephson coupling. Both dc and ac conductivities and localization lengths are obtained. Consequences for the superconducting ladder compound Sr$_x$Ca$_{14-x}$Cu$_{24}$O$_{41+\delta}$ are discussed.