Theory of magnons in spin systems with Dzyaloshinskii-Moriya interaction

TL;DR

This paper develops a theoretical framework to analyze magnon excitations in spin systems with Dzyaloshinskii-Moriya interaction, revealing how non-collinear ground states and surface effects influence magnetic properties.

Contribution

It introduces a self-consistent Green's function approach to study spin-wave spectra and magnetizations in systems with Dzyaloshinskii-Moriya interaction across various dimensions.

Findings

Non-collinear ground states arise from competition between J and D.

Surface effects significantly modify magnetic properties.

Analytical validation of the Green's function method.

Abstract

We study in this paper magnetic properties of a system of quantum Heisenberg spins interacting with each other via a ferromagnetic exchange interaction J and an in-plane Dzyaloshinskii-Moriya interaction D. The non-collinear ground state due to the competition between J and D is determined. We employ a self-consistent Green'function theory to calculate the spin-wave spectrum and the layer magnetizations at finite T in two and three dimensions as well as in a thin film with surface effects. Analytical details and the validity of the method are shown and discussed.