Influence of disorder on incoherent transport near the Mott transition

TL;DR

This paper investigates how disorder affects electrical transport near the Mott transition, revealing that disorder broadens the bandwidth and enhances metallic behavior without creating new charge carriers, aligning with recent experimental observations.

Contribution

It provides a detailed calculation of optical and DC conductivity in a disordered Hubbard model near the Mott transition, highlighting disorder's role in modifying metallic properties.

Findings

Large resistivity driven by inelastic scattering persists despite disorder.

Disorder broadens bandwidth and induces effective local doping, increasing metallicity.

Optical conductivity retains a Drude-like peak even at high resistivity.

Abstract

We calculate the optical and DC conductivity for half-filled disordered Hubbard model near the Mott metal-insulator transition. As in the clean case, large metallic resistivity is driven by a strong inelastic scattering, and Drude-like peak in the optical conductivity persists even at temperatures when the resistivity is well beyond the semiclassical Mott-Ioffe-Regel limit. Local random potential does not introduce new charge carriers, but it induces effective local carrier doping and broadens the bandwidth. This makes the system more metallic, in agreement with the recent experiments on X-ray irradiated charge-transfer salts.