Origin of giant spin-lattice coupling and the suppression of ferroelectricity in EuTiO3 from first principles

TL;DR

This study uses first-principles calculations to reveal how Eu 4f electron hybridization suppresses ferroelectricity and enhances octahedral rotations in EuTiO3, highlighting the role of rare-earth electrons in lattice stability.

Contribution

It uncovers the microscopic mechanism behind ferroelectric suppression and spin-phonon coupling in EuTiO3, emphasizing the impact of Eu 4f states on lattice dynamics.

Findings

Eu 4f hybridization drives away from ferroelectricity

Magnetic order influences hybridization and spin-phonon coupling

Rare-earth f electrons are crucial for lattice stability

Abstract

We elucidate the microscopic mechanism that causes a suppression of ferroelectricity and an enhancement of octahedral rotations in EuTiO3 from first principles. We find that the hybridization of the rare-earth Eu 4f states with the B-site Ti cation drives the system away from ferroelectricity. We also show that the magnetic order dependence of this hybridization is the dominant source of spin-phonon coupling in this material. Our results underline the importance of rare-earth f electrons on the lattice dynamics and stability of these transition metal oxides.