Toroidal Scattering and Nonreciprocal Transport by Magnetic Impurities

TL;DR

This paper introduces a mechanism where magnetic impurities with toroidal moments induce nonreciprocal electron transport in metals by locally breaking inversion symmetry, relevant for systems with spin-orbit coupling.

Contribution

It presents a novel second-order response mechanism involving magnetic impurities with toroidal moments causing nonreciprocal transport in metals.

Findings

Magnetic impurities with toroidal moments scatter electrons asymmetrically.

The mechanism applies to impurities off inversion centers like surfaces or interstitial sites.

Nonreciprocal responses are ubiquitous in such impurity configurations.

Abstract

We propose the second-order response of metals in an electric field induced by magnetic impurities which locally break inversion symmetry. The impurities with toroidal moments scatter conduction electrons in the presence of the spin-orbit coupling, leading to nonreciprocal response. This mechanism is ubiquitous when a magnetic impurity is placed off an inversion center such as an interstitial site and a surface of a two-dimensional system.