Giant current-driven domain wall mobility in (Ga,Mn)As

TL;DR

This paper theoretically demonstrates that spin-orbit coupling in (Ga,Mn)As significantly enhances domain wall mobility by causing hole reflection and increased non-adiabatic torque, aligning with experimental observations.

Contribution

It reveals the crucial role of spin-orbit coupling in dramatically increasing current-driven domain wall mobility in (Ga,Mn)As, a novel insight for spintronic applications.

Findings

Hole reflection at domain walls due to spin-orbit coupling increases non-adiabatic torque.

Domain wall mobility is enhanced by three to four orders of magnitude.

Calculated mobilities agree with experimental data.

Abstract

We study theoretically hole current-driven domain wall dynamics in (Ga,Mn)As. We show that the spin-orbit coupling causes significant hole reflection at the domain wall, even in the adiabatic limit when the wall is much thicker than the Fermi wavelength, resulting in spin accumulation and mistracking between current-carrying spins and the domain wall magnetization. This increases the out-of-plane non-adiabatic spin transfer torque and consequently the current-driven domain wall mobility by three to four orders of magnitude. Trends and magnitude of the calculated domain wall current mobilities agree with experimental findings.