Effect of disorder on superconductivity and Rashba spin-orbit coupling in LaAlO3/SrTiO3 interfaces

TL;DR

This study investigates how disorder introduced by Cr doping affects superconductivity and Rashba spin-orbit coupling in LaAlO3/SrTiO3 interfaces, revealing increased electron interactions and a D'Yakonov-Perel relaxation mechanism.

Contribution

It demonstrates the impact of Cr-induced disorder on superconductivity and spin-orbit coupling, providing insights into their interplay in oxide interfaces.

Findings

Superconducting Tc decreases with Cr doping.

Spin-orbit coupling evolves with gate voltage and doping.

Spin relaxation follows a D'Yakonov-Perel mechanism.

Abstract

A rather unique feature of the two-dimensional electron gas (2-DEG) formed at the interface between the two insulators LaAlO3 and SrTiO3 is to host both gate-tunable superconductivity and strong spin-orbit coupling. In the present work, we use the disorder generated by Cr substitution of Al atoms in LaAlO3 as a tool to explore the nature of superconductivity and spin-orbit coupling in these interfaces. A reduction of the superconducting Tc is observed with Cr doping consistent with an increase of electron-electron interaction in presence of disorder. In addition, the evolution of spin-orbit coupling with gate voltage and Cr doping suggests a D'Yakonov-Perel mechanism of spin relaxation in the presence of a Rashba-type spin-orbit interaction.