Optical spin transfer and spin-orbit torques in thin-film ferromagnets

Published

August 30, 2017

Author(s)

Junwen Li, Paul M. Haney

Abstract

We study the optically induced torques on thin film ferromagnetic layers under excitation by circularly polarized light. We include Rashba spin-orbit coupling and assume an out-of-plane magnetization, and consider incident light with an in-plane component of angular momentum (e.g. light with an oblique angle of incidence). Solving the semiconductor Bloch equations, we find simple expressions for the torque per optical absorption rate in the limits of weak and strong spin-orbit coupling. For weak spin-orbit coupling, the torque is bounded by the optical angular momentum injection rate. For strong spin-orbit coupling, the torque can exceed the angular momentum injection rate by a factor $\Δ\tau/\hbar$, where $\Δ$ is the magnetic exchange splitting and $\tau$ is the carrier scattering time.

Citation

Physical Review B

Volume

96

Issue

5

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevB.96.054447

Keywords

Organometal Halide Perovskite, Rashba, Inversion Symmetry Breaking, Spin-Orbit Torque

Citation

Li, J. and Haney, P. (2017), Optical spin transfer and spin-orbit torques in thin-film ferromagnets, Physical Review B, [online], https://doi.org/10.1103/PhysRevB.96.054447 (Accessed October 12, 2025)