Ferroelectricity from spin supercurrents in LiCuVO4

TL;DR

This paper demonstrates that in LiCuVO4, ferroelectricity arises from spin supercurrents rather than static Dzyaloshinskii-Moriya interactions or exchange striction, confirmed through neutron studies and thermodynamic measurements.

Contribution

It provides experimental evidence supporting a purely electronic mechanism for magnetoelectric coupling via spin supercurrents in LiCuVO4.

Findings

Static Dzyaloshinskii-Moriya interaction is absent.

Exchange striction is negligible in LiCuVO4.

Magnetoelectric coupling aligns with spin supercurrent theory.

Abstract

We have studied the magnetic structure of the ferroelectric frustrated spin-1/2 chain material LiCuVO4 in applied electric and magnetic fields using polarized neutrons. A symmetry and mean-field analysis of the data rules out the presence of static Dzyaloshinskii-Moriya interaction, while exchange striction is shown to be negligible by our specific-heat measurements. The experimentally observed magnetoelectric coupling is in excellent agreement with the predictions of a purely electronic mechanism based on spin supercurrents.