Dzyaloshinskii-Moriya Interaction and Spiral Order in Spin-orbit Coupled Optical Lattices

TL;DR

This paper explores how spin-orbit coupling in ultracold atomic gases within optical lattices can induce Dzyaloshinskii-Moriya interactions, leading to spin spiral order and multiferroic effects, with phase diagrams analyzed through Monte Carlo simulations.

Contribution

It derives an effective spin model incorporating DM interactions in optical lattices and demonstrates the potential for strong DM interactions under realistic experimental conditions.

Findings

Strong DM interactions can be realized in optical lattices.

Finite temperature phase diagrams show diverse spin orders.

Spin spiral order can be controlled via spin-orbit coupling and Zeeman fields.

Abstract

We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations.