Derivation of Spin Torques of the Magnetic System in Broken Inversion Symmetry

TL;DR

This paper introduces a novel theoretical framework for deriving spin torques in magnetic systems with broken inversion symmetry, integrating various spin interactions into a unified spin dynamics model.

Contribution

It presents a new method using asymmetric spin-spin interactions to derive effective fields and spin torques, unifying Dzyaloshinskii-Moriya interaction, spin transfer, and spin-orbit torques.

Findings

Derived spin torques from effective fields in broken inversion symmetry systems.

Unified different spin interactions into a comprehensive spin dynamics model.

Compared new approach with traditional spin dynamics methods.

Abstract

We propose a new approach to derive spin torque in systems of broken inversion symmetry. It uses the concepts of asymmetric and directional spin-spin interactions to obtain their effective fields. We applied the effective fields into the Landau-Lifshitz equation and obtained spin torques. The model offers a new and general approach for spin dynamics, one that effectively merges the Dzyaloshinskii-Moriya interaction, spin transfer torques, and spin-orbit torque into the spin dynamics equation. We discussed how our model is imposed on the spin dynamics and compared our approach with the traditional discussions on spin dynamics.