Uniaxial spin texture in a superconducting electron gas revealed by exchange interactions

TL;DR

This study uncovers a uniaxial spin texture in a 2D superconducting electron gas at EuOx/KTaO3 interfaces, revealing exchange interactions that could advance quantum and spintronic applications.

Contribution

It demonstrates the presence of a highly anisotropic 'half-Rashba' spin texture in a 2DEG at a magnetic interface, revealing hidden spin structures through exchange interactions.

Findings

Uniaxial in-plane anisotropy observed in EuOx/KTaO3 (110) interface

Spin texture consistent with a 'half-Rashba' model

Exchange interactions reveal hidden spin structures

Abstract

Two-dimensional superconductors with spin-textured Fermi surfaces can be a platform for realizing unconventional pairing states and are of substantial interest in the context of quantum information science, and superconducting spintronics/orbitronics. We observed an unusual in-plane uniaxial anisotropy in the superconducting 2D electron gas (2DEG) formed at EuOx/KTaO3 (110) interfaces, where the EuOx is magnetic. This anisotropy is not evident in AlOx/KTaO3 (110) where the overlayer is non-magnetic. Our results are consistent with a highly anisotropic 'half-Rashba' spin-textured Fermi surface in 2DEGs formed at the KTaO3 (110) interface that is hidden from external magnetic fields due to a near cancellation between orbital and spin moments but revealed by exchange interactions of the electrons in the 2DEG with Eu moments near the EuOx/KTaO3 (110) interface. The interactions between the uniaxial spin texture and the magnetic overlayer offer new ways to explore the interplay between magnetism and 2D superconductivity.