First-Principles Calculation of the Spin-Orbit Torques in a Co/Pt Bilayer

Authors

K. D. Belashchenko, University of Nebraska-LincolnFollow
Alexey A. Kovalev, University of Nebraska-LincolnFollow
M. van Schilfgaarde, Kings College LondonFollow

Document Type

Article

Date of this Version

10-2018

Citation

arXiv:1810.11003

Comments

Copyright © 2018 K. D. Belashchenko, A. A. Kovalev, and M. van Schilfgaarde. Used by permission.

Abstract

The spin-orbit torque in a disordered Co/Pt bilayer is calculated using a first-principles nonequilibrium Green's function formalism. The torque is formally split in the Fermi-sea and Fermi-surface contributions. The Fermi-sea term is important at low temperatures, but the Fermi-surface term dominates at room temperature. In addition to the usual damping-like and field-like terms, the odd torque contains a sizeable planar Hall-like term (m . E)m x (z x m) which contributes to damping. While the torques that contribute to damping are almost entirely due to spin-orbit coupling on the Pt atoms, the field-like torque does not require it.