Weak localization of magnons in a disordered two-dimensional antiferromagnet

TL;DR

This paper investigates how disorder causes weak localization of magnons in a 2D antiferromagnet, leading to a logarithmic decrease in thermal conductivity, with implications for controlling magnon currents.

Contribution

It introduces the concept of weak localization of magnons in disordered 2D antiferromagnets and derives the resulting thermal conductivity behavior.

Findings

Logarithmic suppression of thermal conductivity due to weak localization.

Enhanced back scattering from impurity scattering.

Potential control of magnon thermal currents.

Abstract

We propose the weak localization of magnons in a disordered two-dimensional antiferromagnet. We derive the longitudinal thermal conductivity $\kappa_{xx}$ for magnons of a disordered Heisenberg antiferromagnet in the linear-response theory with the linear-spin-wave approximation. We show that the back scattering of magnons is enhanced critically by the particle-particle-type multiple impurity scattering. This back scattering causes a logarithmic suppression of $\kappa_{xx}$ with the length scale in two dimensions. We also argue a possible effect of inelastic scattering on the temperature dependence of $\kappa_{xx}$. This weak localization is useful to control turning the magnon thermal current on and off.