Electric field effect on spin waves and magnetization dynamics: role of magnetic moment current

TL;DR

This paper demonstrates that a static electric field shifts spin wave dispersion via magnetic moment currents, introducing a tunable, Dzyaloshinskii-Moriya-like interaction independent of magneto-electric effects.

Contribution

It reveals a novel electric field-induced shift in spin wave dispersion caused by magnetic moment currents, extending to a dynamic, tunable interaction similar to Dzyaloshinskii-Moriya interaction.

Findings

Electric field shifts spin wave dispersion relation.

Magnetic moment current causes phase shift akin to Aharonov-Casher effect.

Electric field induces a tunable, Dzyaloshinskii-Moriya-like interaction.

Abstract

We show that a static electric field $E_x$ gives rise to a shift of the spin wave dispersion relation $\omega(q_y-q_E)$ in the direction of the wavenumber $q_y$ of the quantity $q_E=-\gamma_LE_x/c^2$. This effect is caused by the magnetic moment current carried by the spin wave itself that generates an additional phase proportional to the electric field, as in the Aharonov-Casher effect. This effect is independent from the possibly present magneto-electric effects of insulating ferromagnets and superimposes to them. By extending this picture to arbitrary magnetization dynamics, we find that the electric field gives rise to a dynamic interaction term which has the same chiral from of the Dzyaloshinskii-Moriya interaction but is fully tunable with the applied electric field.