Experimental Evidence of t2g Electron-Gas Rashba Interaction Induced by Asymmetric Orbital Hybridization

TL;DR

This study demonstrates how asymmetric orbital hybridization at oxide interfaces can be used to control Rashba spin-orbit interaction, with potential applications in spintronics, verified through experimental and computational methods.

Contribution

It introduces a novel method to tune Rashba interaction by modifying orbital hybridization with a LaFeO3 layer at the LaAlO3/SrTiO3 interface.

Findings

Large Rashba spin-orbit effect achieved without external bias.

Asymmetric orbital hybridization modulated by LaFeO3 layer.

Experimental and first-principles verification of Rashba control.

Abstract

We report the control of Rashba spin-orbit interaction by tuning asymmetric hybridization between Ti-orbitals at the LaAlO3/SrTiO3 interface. This asymmetric orbital hybridization is modulated by introducing a LaFeO3 layer between LaAlO3 and SrTiO3, which alters the Ti-O lattice polarization and traps interfacial charge carriers, resulting in a large Rashba spin-orbit effect at the interface in the absence of an external bias. This observation is verified through high-resolution electron microscopy, magneto-transport and first-principles calculations. Our results open hitherto unexplored avenues of controlling Rashba interaction to design next-generation spin-orbitronics.