Electric dipole moment as descriptor for interfacial Dzyaloshinskii-Moriya interaction

TL;DR

This paper introduces electric dipole moments as effective descriptors for designing chiral magnetic multilayers by linking them to the Dzyaloshinskii-Moriya interaction, simplifying its determination.

Contribution

It derives a new expression connecting electric dipole moments to DMI and validates this approach through density functional theory calculations on multilayers.

Findings

Electric dipole moments correlate linearly with DMI contributions.

The non-magnetic layer Z influences the DMI at the Co-Pt interface.

A linear relation exists between Pt's electric dipole moment, Z's electronegativity, and DMI contribution.

Abstract

Chiral magnets are of fundamental interest and have important technological ramifications. The origin of chiral magnets lies in the Dzyaloshinskii-Moriya interaction (DMI), an interaction whose experimental and theoretical determination is laborious. We derive an expression that identifies the electric dipole moment as descriptor for the systematic design of chiral magnetic multilayers. Using density functional theory calculations, we determine the DMI of (111)-oriented metallic ferromagnetic $Z$/Co/Pt multilayers of ultrathin films. The non-magnetic layer $Z$ determines the DMI at the Co-Pt interface. The results validate the electric and magnetic dipole moments as excellent descriptors. We found a linear relation between the electric dipole moment of Pt, the Allen electronegativity of $Z$, and the contribution of Pt to the total DMI.