# Epitaxial-strain-induced multiferroicity in SrMnO$_{3}$ from first principles

## TL;DR

This study uses first-principles calculations to show how epitaxial strain can induce multiferroicity in SrMnO3, transforming it from an antiferromagnetic paraelectric to a ferroelectric-ferromagnetic state with significant polarization and magnetic responses.

## Contribution

It demonstrates the emergence of multiferroic behavior in SrMnO3 driven by epitaxial strain, a novel finding in the context of first-principles studies of this material.

## Key findings

- Epitaxial strain induces a multiferroic ferroelectric-ferromagnetic state in SrMnO3.
- The predicted polarization exceeds 54 μC/cm^2.
- Estimated Curie temperature for ferromagnetic ordering is above 92 K.

## Abstract

First-principles density-functional calculations reveal a large spin-phonon coupling in cubic SrMnO$_{3}$, with ferromagnetic ordering producing a polar instability. Through combination of this coupling with the strain-polarization coupling characteristic of perovskites, the bulk antiferromagnetic paraelectric ground state of SrMnO$_3$ is shown to be driven to a previously unreported multiferroic ferroelectric-ferromagnetic state by increasing epitaxial strain, both tensile and compressive. This state has a computed polarization and estimated Curie temperature above 54 $\mu$C/cm$^2$ and 92 K. Large mixed magnetic-electric-elastic responses are predicted in the vicinity of the phase boundaries.