Microscopic Origin of the Electric Dzyaloshinskii-Moriya Interaction

TL;DR

This paper uncovers the microscopic origin of the electric Dzyaloshinskii-Moriya interaction (eDMI) through analytical and first-principles calculations, revealing its electron-mediated nature and potential to induce novel topological phases.

Contribution

It provides a detailed microscopic analysis of eDMI, showing its higher-order dependence on atomic displacements and proposing the emergence of chiral electric bobbers.

Findings

eDMI originates from electron hopping activated by local inversion symmetry breaking

eDMI energy is at least third-order in atomic displacements

Chiral electric bobbers can arise from eDMI

Abstract

The microscopic origin of the electric Dzyaloshinskii-Moriya interaction (eDMI) is unveiled and discussed by analytical analysis and first-principles based calculations. As similar to the magnetic Dzyaloshinskii-Moriya interaction (mDMI), eDMI also originates from electron-mediated effect and more specifically from certain electron hoppings that are being activated due to certain local inversion symmetry breaking. However, the eDMI energy is found to be at least a third-order interaction in atomic displacements instead of bilinear in magnetic dipole moments for mDMI. Furthermore, the eDMI energy form is presented, and we find that novel electrical topological defects (namely, chiral electric bobbers) can arise from this eDMI. Thus unraveling the microscopic origin of eDMI has the potential to lead to, and explain, the discovery of novel polar topological phases.