Electrical Control of Large Rashba Effect in Oxide Heterostructures

TL;DR

This study demonstrates how large, tunable Rashba effects in oxide heterostructures can be controlled via electric fields and ferroelectric polarization, advancing spintronic device applications.

Contribution

The paper introduces a first-principles approach to achieve reversible and controllable Rashba splitting in oxide heterostructures through ferroelectric polarization switching.

Findings

Large Rashba splitting is locked at the conduction band minimum.

Reversible Rashba spin texture achieved with polarization switching.

Tuning local ferroelectric displacement alters Rashba splitting strength.

Abstract

Large Rashba effect efficiently tuned by an external electric field is highly desired for spintronic devices. Using first-principles calculations, we demonstrate that large Rashba splitting is locked at conduction band minimum in ferroelectric Bi(Sc/Y/La/Al/Ga/In)O3/PbTiO3 heterostructures where the position of Fermi level is precisely controlled via its stoichiometry. Fully reversible Rashba spin texture and drastic change of Rashba splitting strength with ferroelectric polarization switching are realized in the symmetric and asymmetric heterostructures, respectively. By artificially tuning the local ferroelectric displacement and the orbital hybridization, the synergetic effect of local potential gradient and orbital overlap on the dramatic change of splitting strength is confirmed. These results improve the feasibility of utilizing Rashba spin-orbit coupling in spintronic devices.