Strain-induced large spin splitting and persistent spin helix at LaAlO$_3$/SrTiO$_3$ interface

TL;DR

This study demonstrates that tensile strain at the LaAlO₃/SrTiO₃ interface significantly enhances spin splitting and induces a persistent spin helix, which could improve spintronic device performance.

Contribution

It reveals how tensile strain controls spin-orbit coupling and spin textures, introducing a method to manipulate spin properties in oxide interfaces.

Findings

Spin-orbit coupling coefficient increased up to 5 times with 7% tensile strain.

Persistent spin helix observed under tensile strain, indicating long spin lifetime.

Strain control offers potential for spinFET and spin-to-charge conversion applications.

Abstract

We investigated the effect of the tensile strain on the spin splitting at the n-type interface in LaAlO$_3$/SrTiO$_3$ in terms of the spin-orbit coupling coefficient $\alpha$ and spin texture in the momentum space using first-principles calculations. We found that the $\alpha$ could be controlled by the tensile strain and be enhanced up to 5 times for the tensile strain of 7%, and the effect of the tensile strain leads to a persistent spin helix, which has a long spin lifetime. These results support that the strain effect on LaAlO$_3$/SrTiO$_3$ is important for various applications such as spinFET and spin-to-charge conversion.