# Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces

## TL;DR

This paper explores how density inhomogeneities and Rashba spin-orbit coupling interact in oxide interfaces, revealing their role in electronic phase separation, inhomogeneous spin currents, and potential spintronic applications.

## Contribution

It introduces a phenomenological model linking density-dependent Rashba spin-orbit coupling to inhomogeneity effects in oxide interface 2DEGs, highlighting novel physical phenomena.

## Key findings

- Inhomogeneous Rashba spin-orbit coupling causes spin-current inhomogeneity.
- Density-dependent RSOC leads to inhomogeneous quantum Hall states.
- Inhomogeneous RSOC can enable disorder-robust spin Hall effects.

## Abstract

There is steadily increasing evidence that the two-dimensional electron gas (2DEG) formed at the interface of some insulating oxides like LaAlO3/SrTiO3 and LaTiO3/SrTiO3 is strongly inhomogeneous. The inhomogeneous distribution of electron density is accompanied by an inhomogeneous distribution of the (self-consistent) electric field confining the electrons at the interface. In turn this inhomogeneous transverse electric field induces an inhomogeneous Rashba spin-orbit coupling (RSOC). After an introductory summary on two mechanisms possibly giving rise to an electronic phase separation accounting for the above inhomogeneity,we introduce a phenomenological model to describe the density-dependent RSOC and its consequences. Besides being itself a possible source of inhomogeneity or charge-density waves, the density-dependent RSOC gives rise to interesting physical effects like the occurrence of inhomogeneous spin-current distributions and inhomogeneous quantum-Hall states with chiral "edge" states taking place in the bulk of the 2DEG. The inhomogeneous RSOC can also be exploited for spintronic devices since it can be used to produce a disorder-robust spin Hall effect.