Spin-current driven Dzyaloshinskii-Moriya interaction in the multiferroic BiFeO3 from first-principles

TL;DR

This study uses first-principles calculations to analyze the spin-current driven Dzyaloshinskii-Moriya interaction in BiFeO3, revealing its origin, anisotropy, and significance for electrical control of magnons in multiferroics.

Contribution

It identifies the dominant spin-current model contribution to the DM interaction in BiFeO3 and explores its anisotropic effects on magnon dispersion.

Findings

Only one DM interaction contribution from the spin current model.

Exchange interaction is isotropic, but DM interaction is anisotropic.

Spin current-induced asymmetry dominates over structural asymmetry.

Abstract

The electrical control of magnons opens up new ways to transport and process information for logic devices. In magnetoelectrical multiferroics, the Dzyaloshinskii-Moriya (DM) interaction directly allow for such a control and, hence, is of major importance. We determine the origin and the strength of the (converse) spin current DM interaction in the R3c bulk phase of the multiferroic BiFeO3 based on density functional theory. Our data supports only the existence of one DM interaction contribution originating from the spin current model. By exploring then magnon dispersion in the full Brillouin Zone, we show that the exchange is isotropic, but the DM interaction and anisotropy prefer any propagation and any magnetization direction within the full (111) plane. Our work emphasizes the significance of the asymmetric potential induced by the spin current over the structural asymmetry induced by the anionic octahedron in multiferroics such as BiFeO3.