Anti-Localisation to Strong Localisation: The Interplay of Magnetic Scattering and Structural Disorder

TL;DR

This paper investigates how magnetic scattering influences electrical transport in strongly disordered systems, revealing complex transitions between insulating and metallic states due to the interplay of magnetic effects and structural disorder.

Contribution

It provides a detailed analysis of magnetic scattering effects on transport in strongly disordered systems, including phase diagrams and re-entrant insulator-metal-insulator transitions.

Findings

Weak coupling reduces resistivity via suppression of localization effects.

Strong coupling increases disorder, sharply raising resistivity.

Identifies re-entrant insulator-metal-insulator transition in phase diagram.

Abstract

We study the effect of magnetic scattering on transport in a system with strong structural disorder, using exact finite size calculation of the low frequency optical conductivity. At weak electron-spin coupling spin disorder leads to a decrease in resistivity by weakening the quantum interference precursors to Anderson localisation. However, at strong electron-spin coupling, the double exchange limit, magnetic scattering increases the effective disorder, sharply increasing the resistivity. We illustrate the several unusual transport regimes in this strong disorder problem, identify a re-entrant insulator-metal-insulator transition, and map out the phase diagram at a generic electron density.