Magnetoelectric effect due to local noncentrosymmetry

TL;DR

This paper presents a microscopic model explaining the magnetoelectric effect in materials with ions in noncentrosymmetric environments, emphasizing the role of spin-orbit coupling in generating electric polarization.

Contribution

It introduces a novel microscopic model linking local noncentrosymmetry and spin-orbit coupling to magnetoelectric polarization, applicable to various magnetic structures.

Findings

Model explains polarization in MnWO4, MnPS3, LiNiPO4

Accounts for both commensurate and incommensurate magnetic structures

Provides a framework for understanding magnetoelectric effects in complex materials

Abstract

Magnetoelectrics often possess ions located in noncentrosymmetric surroundings. Based on this fact we suggest a microscopic model of magnetoelectric interaction and show that the spin-orbit coupling leads to spin-dependent electric dipole moments of the electron orbitals of these ions, which results in non-vanishing polarization for certain spin configurations. The approach accounts for the macroscopic symmetry of the unit cell and is valid both for commensurate and complex incommensurate magnetic structures. The model is illustrated by the examples of MnWO4, MnPS3 and LiNiPO4. Application to other magnetoelectrics is discussed.