Relationship between ferroelectricity and Dzyaloshinskii-Moriya interaction in multiferroics and the effect of bond-bending

TL;DR

This paper investigates the microscopic link between ferroelectricity and Dzyaloshinskii-Moriya interaction in multiferroics, demonstrating how bond-bending in transition metal oxides can enhance ferroelectric properties.

Contribution

It provides a detailed analysis of the spin current model, establishing the relation between ferroelectricity and Dzyaloshinskii-Moriya interaction, and highlights the role of bond-bending in enhancing ferroelectricity.

Findings

Established the relation between ferroelectricity and Dzyaloshinskii-Moriya interaction.

Derived a simple relation between electric polarization and magnetic wave vector.

Showed bond-bending in transition metal oxides enhances ferroelectricity.

Abstract

We studied the microscopic mechanism of multiferroics, in particular with the "spin current" model (Hosho Katsura, Naoto Nagaosa and Aleander V. Balatsky, Phys. Rev. Lett. 95, 057205 (2005)). Starting from a system with helical spin configuration, we solved for the forms of the electron wave functions and analyzed their characteristics. The relation between ferroelectricity and Dzyaloshinskii-Moriya interaction (I. Dzyaloshinskii, J. Phys. Chem. Solids 4, 241 (1958) and T. Moriya, Phys. Rev. 120, 91 (1960)) is clearly established. There is also a simple relation between the electric polarization and the wave vector of magnetic orders. Finally, we show that the bond-bending exists in transition metal oxides can enhance ferroelectricity.