Spin and Orbital Rashba effects at the Ni/HfO$_2$ interface

TL;DR

This paper predicts that electric gating can reversibly control magnetic and spin-orbital properties at the Ni/HfO2 interface, enabling low-energy spintronic and orbitronic devices through giant modulation of interfacial effects.

Contribution

It introduces a novel prediction of electric control over magnetocrystalline anisotropy and Rashba effects at Ni/HfO2 interfaces using ab initio simulations.

Findings

Reversible electric control of magnetocrystalline anisotropy from in-plane to out-of-plane.

Modulation of spin and orbital densities by approximately 50% and 30%.

Potential for voltage-controlled spin- and orbitronics devices.

Abstract

We predict the giant ferroelectric control of interfacial properties of Ni/HfO2, namely, (i) the magnetocrystalline anisotropy and (ii) the inverse spin and orbital Rashba effects. The reversible control of magnetic properties using electric gating is a promising route to low-energy consumption magnetic devices, including memories and logic gates. Synthetic multiferroics, composed of a ferroelectric in proximity to a magnet, stand out as a promising platform for such devices. Using a combination of $ab$ $initio$ simulations and transport calculations, we demonstrate that reversing the electric polarization modulates the interface magnetocrystalline anisotropy from in-plane to out-of-plane. This modulation compares favorably with recent reports obtained upon electromigration induced by ionic gating. In addition, we find that the current-driven spin and orbital densities at the interface can be modulated by about 50% and 30%, respectively. This giant modulation of the spin-charge and orbit-charge conversion efficiencies opens appealing avenues for voltage-controlled spin- and orbitronics devices.