Observation of out-of-plane spin texture in a SrTiO3 (111) two-dimensional electron gas

TL;DR

This study reveals an out-of-plane spin component in the SrTiO3 (111) 2DEG, detected via BMER, supported by calculations, indicating a universal property of oxide 2DEGs with potential for tunable spintronic applications.

Contribution

It demonstrates the presence of out-of-plane spin texture in SrTiO3 (111) 2DEG using BMER measurements and theoretical calculations, highlighting a new aspect of spin structure in oxide interfaces.

Findings

Out-of-plane spin component detected via BMER.

Relativistic calculations confirm the spin texture.

BMER response is large and tunable.

Abstract

We explore the second order bilinear magnetoelectric resistance (BMER) effect in the d-electron-based two-dimensional electron gas (2DEG) at the SrTiO3 (111) surface. We find an evidence of a spin-split band structure with the archetypal spin-momentum locking of the Rashba effect for the in-plane component. Under an out-of-plane magnetic field, we find a BMER signal that breaks the six-fold symmetry of the electronic dispersion, which is a fingerprint for the presence of a momentum dependent out-of-plane spin component. Relativistic electronic structure calculations reproduce this spin-texture and indicate that the out-of-plane component is a ubiquitous property of oxide 2DEGs arising from strong crystal field effects. We further show that the BMER response of the SrTiO3 (111) 2DEG is tunable and unexpectedly large.