First Principles Study of Structural, Electronic and Magnetic Interplay in Ferroelectromagnetic Yttrium Manganite

TL;DR

This study uses first-principles calculations to explore the structural, electronic, and magnetic interactions in yttrium manganite, revealing how different crystal structures influence ferroelectricity and magnetism.

Contribution

It provides a detailed comparison of ferroelectric and non-ferroelectric phases of YMnO3, explaining the electronic and structural origins of ferroelectric distortion.

Findings

Hexagonal phase exhibits electronic configuration conducive to ferroelectricity.

Orthorhombic phase shows Jahn-Teller distortion due to crystal field splitting.

Magnetic moments on Mn3+ ions are essential for ferroelectric distortion.

Abstract

We present results of local spin density approximation pseudopotential calculations for the ferroelectromagnet, yttrium manganite (YMnO3). The origin of the differences between ferroelectric and non-ferroelectric perovskite manganites is determined by comparing the calculated properties of yttrium manganite in its ferroelectric hexagonal and non-ferroelectric orthorhombic phases. In addition, orthorhombic YMnO3 is compared with the prototypical non-ferroelectric manganite, lanthanum manganite. We show that, while the octahedral crystal field splitting of the cubic perovskite structure causes a centro-symmetric Jahn-Teller distortion around the Mn3+ ion, the markedly different splitting in hexagonal perovskites creates an electronic configuration consistent with ferroelectric distortion. We explain the nature of the distortion, and show that a local magnetic moment on the Mn3+ ion is a requirement for it to occur.