First-principles study of ferroelectricity induced by p-d hybridization in ferrimagnetic NiFe2O4

TL;DR

This study uses first-principles density functional calculations to explore the origin of ferroelectricity in NiFe2O4, revealing a significant polarization driven by p-d hybridization and Jahn-Teller effects.

Contribution

It provides a detailed first-principles analysis of ferroelectricity in NiFe2O4, highlighting the role of p-d hybridization and identifying the most stable magnetic configuration.

Findings

Spontaneous polarization of 23 μC/cm² along z direction.

Ferroelectricity originates from p-d hybridization influenced by Jahn-Teller effect.

Most stable magnetic configuration determined through energy calculations.

Abstract

We investigate the ferrimagnetism and ferroelectricity of bulk NiFe$_2$O$_4$ with tetragonal $P4_122$ ~symmetry by means of density functional calculations using generalized gradient approximation + Hubbard $U$ approach. Special attention is paid to finding the most energetically favorable configuration on magnetic ordering and further calculating the reliable spontaneous electric polarization. With the fully optimized crystalline structure of the most stable configuration, the spontaneous polarization is obtained to be 23 $\mu$C/cm$^2$ along the z direction, which originates from the hybridization between the 3d states of the Fe$^{3+}$ cation and the 2p states of oxygen induced by Jahn-Teller effect.