Thermal transport properties of disordered spin-1/2 systems

TL;DR

This paper investigates how disorder affects heat transport in spin-1/2 chains, specifically analyzing the XX model as a noninteracting fermion system, and examines the frequency-dependent thermal conductivity at finite temperatures.

Contribution

It provides a numerical analysis of thermal transport in disordered spin chains using fermion representation, highlighting the impact of disorder on conductivity properties.

Findings

Disorder destroys ballistic heat transport in the chain.

Thermal conductivity shows frequency dependence influenced by disorder.

Comparison with spin conductivity reveals qualitative differences.

Abstract

This work studies heat transport of bond-disordered spin-1/2 chains. As an example, the XX case is analyzed, which corresponds to a model of noninteracting spinless fermions. Within the fermion representation, the single-particle eigenenergies are determined numerically, which allow one to compute transport coefficients. Since the ballistic transport properties of a clean chain are destroyed by disorder, the focus is on the frequency dependence of the thermal conductivity and on a qualitative comparison with the spin conductivity, both at finite temperatures.