Impurity-induced orbital magnetization in a Rashba electron gas

TL;DR

This paper explores how magnetic impurities induce oscillating orbital magnetization in a Rashba electron gas, revealing complex interactions between spin, orbital effects, and magnetic configurations.

Contribution

It introduces a detailed analysis of impurity-induced orbital magnetization in Rashba systems, including effects of non-collinear magnetic states and higher-order spin chiralities.

Findings

Orbital magnetization oscillates with distance from impurities.

Net orbital magnetization is comparable to spin magnetization.

Higher-order spin chiralities significantly influence magnetization magnitude and sign.

Abstract

We investigate the induced orbital magnetization density in a Rashba electron gas with magnetic impurities. Relying on classical electrodynamics, we obtain this quantity through the bound currents composed of a paramagnetic and a diamagnetic-like contribution which emerge from the spin-orbit interaction. Similar to Friedel charge ripples, the bound currents and the orbital magnetization density oscillate as function of distance away from the impurity with characteristic wavelengths defined by the Fermi energy and the strength of the Rashba spin-orbit interaction. The net induced orbital magnetization was found to be of the order of magnitude of its spin counterpart. Besides the exploration of the impact of the electronic filling of the impurity states, we investigate and analyze the orbital magnetization induced by an equilateral frustrated trimer in various non-collinear magnetic states. On the one hand, we confirm that non-vanishing three-spin chiralities generate a finite orbital magnetization density. On the other hand, higher order contributions lead to multiple-spin chiralities affecting non-trivially and significantly the overall magnitude and sign of the orbital magnetization.