Helicoidal magnetic structure and ferroelectric polarization in Cu3Nb2O8

TL;DR

This study combines first-principles calculations and a spin-induced polarization model to elucidate the magnetic structure and ferroelectric polarization mechanisms in Cu3Nb2O8, revealing the roles of exchange interactions and symmetric exchange striction.

Contribution

It provides a detailed theoretical analysis of the origin of helicoidal magnetic structures and ferroelectric polarization in Cu3Nb2O8, highlighting the mechanisms behind their formation.

Findings

Helicoidal spin state arises from isotropic exchange interactions.

Ferroelectric polarization results from symmetric exchange striction with slight spin canting.

Polarization direction is independent of the spin rotation plane orientation.

Abstract

We investigate the origin of the coplanar helicoidal magnetic structure and the ferroelectric polarization in Cu3Nb2O8 by combining first-principles calculations and our spin-induced ferroelectric polarization model. The coplanar helicoidal spin state comes from the competition between the isotropic exchange interactions, and the ferroelectric polarization from the symmetric exchange striction with slight spin canting. However, the direction of the polarization is not determined by the orientation of the spin rotation plane.