Spin-Orbit Coupling in LaAlO$_3$/SrTiO$_3$ interfaces: Magnetism and Orbital Ordering

TL;DR

This paper explores how Rashba spin-orbit coupling influences magnetism and orbital ordering at LaAlO$_3$/SrTiO$_3$ interfaces, explaining observed magnetic anisotropy and potential impacts on magneto-transport phenomena.

Contribution

It demonstrates how Rashba spin-orbit coupling accounts for magnetic anisotropy and reveals the coupling between magnetic and orbital orderings at the interface.

Findings

Rashba spin-orbit coupling explains magnetic anisotropy.

Orbital imbalance couples with magnetic anisotropy.

Orbital ordering impacts magneto-transport.

Abstract

The combination of Rashba spin-orbit coupling and electron correlations can induce unusual phenomena in the metallic interface between SrTiO$_3$ and LaAlO$_3$. We consider effects of Rashba spin-orbit coupling at this interface in the context of the recent observation of anisotropic magnetism. Firstly, we show how Rashba spin-orbit coupling in a system near a band-edge can account for the observed magnetic anisotropy. Secondly, we investigate the coupling between in-plane magnetic-moment anisotropy and nematicity in the form of an orbital imbalance between d$_{xz}$ / d$_{yz}$ orbitals. We estimate this coupling to be substantial in the low electron density regime. Such an orbital ordering can affect magneto transport.