Coupled magnetic-ferroelectric metal-insulator transitions in epitaxially-strained SrCoO$_{3}$ from first principles

TL;DR

This study uses first-principles calculations to explore how epitaxial strain influences phase transitions in SrCoO3, revealing coupled magnetic and ferroelectric phases with potential for electric and magnetic field control of metal-insulator states.

Contribution

It provides a detailed phase diagram showing strain-induced coupled magnetic and ferroelectric transitions in SrCoO3 from first-principles calculations.

Findings

Epitaxial strain drives phase transitions from ferromagnetic-metallic to antiferromagnetic-insulating-ferroelectric phases.

Coupled phases exhibit low elastic energy and cross responses to electric and magnetic fields.

External stimuli like electric fields or stress can induce insulator-metal transitions in these phases.

Abstract

First-principles calculations of the epitaxial-strain phase diagram of perovskite SrCoO$_{3}$ are presented. Through combination of the large spin-phonon coupling with polarization-strain coupling and coupling of the band gap to the polar distortion, both tensile and compressive epitaxial strain are seen to drive the bulk ferromagnetic-metallic (FM-M) phase to antiferromagnetic-insulating-ferroelectric (AFM-I-FE) phases, the latter having unusually low elastic energy. At these coupled magnetic-ferroelectric metal-insulator phase boundaries, cross responses to applied electric and magnetic fields and stresses are expected. In particular, a magnetic field or compressive uniaxial stress applied to the AFM phases could induce an insulator-metal transition, and an electric field applied to the FM-M phase could induce a metal-insulator transition.