Finite temperature transport in disordered Heisenberg chains

TL;DR

This study investigates how local and bond disorder affect the finite temperature spin and thermal conductivities in disordered Heisenberg chains, revealing finite dc conductivities at high temperatures and nonanalytic low-frequency behavior.

Contribution

It provides numerical evidence on the finite temperature transport properties of disordered Heisenberg chains, highlighting the effects of disorder on conductivity and low-frequency behavior.

Findings

Finite dc conductivities at high temperatures for local disorder.

Vanishing dc transport in the uncorrelated XY case.

Finite dc conductivities at all temperatures except T=0 at strong disorder.

Abstract

Using numerical diagonalization techniques, we explore the effect of local and bond disorder on the finite temperature spin and thermal conductivities of the one dimensional anisotropic spin-1/2 Heisenberg model. High-temperature results for local disorder show that the dc conductivties are finite, apart from the uncorrelated - XY case - where dc transport vanishes. Moreover, at strong disorder, we find finite dc conductivities at all temperatures $T$, except T=0. The low frequency conductivities are characterized by a nonanalytic cusp shape. Similar behavior is found for bond disorder.