# Anisotropy of spin-transfer torques and Gilbert damping induced by Rashba coupling

## TL;DR

This paper investigates how Rashba spin-orbit coupling causes anisotropy in spin-transfer torques, Gilbert damping, and spin renormalization in a 2D ferromagnet, revealing a fundamental relation and implications for magnetic textures.

## Contribution

It provides a microscopic analysis of anisotropic spin phenomena induced by Rashba coupling and establishes a novel relation among STT, GD, and ESR in a 2D ferromagnetic system.

## Key findings

- Identified anisotropic behavior of STT, GD, and ESR due to Rashba coupling.
- Established a relation linking these phenomena in systems with two spin subbands.
- Generalized the concept of spin-polarized current and computed spin susceptibility.

## Abstract

Spin-transfer torques (STT), Gilbert damping (GD), and effective spin renormalization (ESR) are investigated microscopically in a 2D Rashba ferromagnet with spin-independent Gaussian white-noise disorder. Rashba spin-orbit coupling induced anisotropy of these phenomena is thoroughly analysed. For the case of two partly filled spin subbands, a remarkable relation between the anisotropic STT, GD, and ESR is established. In the absence of magnetic field and other torques on magnetization, this relation corresponds to a current-induced motion of a magnetic texture with the classical drift velocity of conduction electrons. Finally, we compute spin susceptibility of the system and generalize the notion of spin-polarized current.