Ferroelectric Control of Metal-Insulator Transition

TL;DR

This paper proposes a method to control the metal-insulator transition in a perovskite material using ferroelectric polarization, achieved through first-principles calculations and interface engineering.

Contribution

It introduces a novel tri-color superlattice design that enables reversible control of the metal-insulator transition via ferroelectric polarization switching.

Findings

Reversing ferroelectric polarization induces a metal-insulator transition in LaNiO₃.

The transition is driven by changes in crystal field splitting and bandwidth of Ni orbitals.

Designing interface structures can potentially realize similar transitions in other materials.

Abstract

We propose a method of controlling the metal-insulator transition of one perovskite material at its interface with a another ferroelectric material based on first principle calculations. The operating principle is that the rotation of oxygen octahedra tuned by the ferroelectric polarization can modulate the superexchange interaction in this perovskite. We designed a tri-color superlattice of (BiFeO$_3$)$_N$/LaNiO$_3$/LaTiO$_3$, in which the BiFeO$_3$ layers are ferroelectric, the LaNiO$_3$ layer is the layer of which the electronic structure is to be tuned, and LaTiO$_3$ layer is inserted to enhance the inversion asymmetry. By reversing the ferroelectric polarization in this structure, there is a metal-insulator transition of the LaNiO$_3$ layer because of the changes of crystal field splitting of the Ni $e_g$ orbitals and the bandwidth of the Ni in-plane $e_g$ orbital. It is highly expected that a metal-transition can be realized by designing the structures at the interfaces for more materials.