Rashba-like spin-orbit interaction and spin texture at the KTaO$_\text{3}$ (001) surface from DFT calculations

TL;DR

This study uses DFT calculations to analyze Rashba-like spin-orbit interaction and spin textures at the KTaO3 (001) surface, revealing strong linear Rashba effects relevant for oxide spintronics.

Contribution

It provides a comprehensive DFT-based analysis of Rashba spin-orbit interaction and spin textures at KTaO3 surfaces, including a proposed electrostatic charge transfer model.

Findings

Strong linear Rashba interaction observed

No evidence of Dresselhaus or higher-order Rashba effects

Analysis applicable to oxide spintronics development

Abstract

Rashba-like spin-orbit interaction at oxide heterostructures emerges as a much sought-after feature in the context of oxide spintronics and spin-orbitronics. KTaO$_3$ (KTO) is one of the best substrates available for the purpose, owing to its strong spin-orbit interaction and alternating $+1|-1$ charged layers along the (001) direction. Employing first-principles calculations within density functional theory (DFT) and proposing a possible electrostatic model for charge transfer to the surfaces of KTO slabs, we comprehensively analyze Rashba-like spin-orbit interaction with the help of three-dimensional band dispersion, isoenergetic contours, and projected spin textures $-$ all directly obtained from our DFT results $-$ in a thin insulating slab and a conducting thick slab of KTO. Our results reveal reasonably strong linear Rashba interaction with no signature of Dresselhaus or higher order Rashba interactions in the systems considered here. The rigorous analysis presented here may be crucial for future developments in oxide spintronics.