Transport properties of a spin-1/2 Heisenberg chain with an embedded spin-S impurity

TL;DR

This paper investigates how a spin-S impurity affects the transport properties of a spin-1/2 Heisenberg chain at finite temperatures, combining numerical and analytical methods to understand impurity screening effects.

Contribution

It provides a detailed numerical and analytical analysis of the impact of a spin-S impurity on the transport in a spin-1/2 Heisenberg chain, including temperature dependence and impurity screening.

Findings

Impurity influences spin and thermal conductivities.

Screening effects depend on temperature and coupling strength.

Chain can be cut or healed by impurity screening.

Abstract

The finite temperature transport properties of a spin-1/2 anisotropic Heisenberg chain with an embedded spin-S impurity are studied. Using primarily numerical diagonalization techniques, we study the dependence of the dynamical spin and thermal conductivities on the lattice size, the magnitude of the impurity spin, the host-impurity coupling, the easy axis anisotropy, as well as the dependence on temperature. Particularly for the temperature dependence, we discuss the screening of the impurity by the chain eventually leading to the cutting or healing of the host chain. Numerical results are supported by analytical arguments obtained in the strong host-impurity coupling regime.