Universal Polar Instability In Highly Orthorhombic Perovskites

Fuente: arXiv
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Autori principali: Scott, Cameron A. M., Bristowe, Nicholas C.
Natura: Preprint
Pubblicazione: 2024
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author Scott, Cameron A. M.
Bristowe, Nicholas C.
author_facet Scott, Cameron A. M.
Bristowe, Nicholas C.
contents The design of novel multiferroic ABO$_3$ perovskites is complicated by the presence of necessary magnetic cations and ubiquitous antiferrodistortive modes, both of which suppress polar distortions. Using first-principles simulations, we observe that the existence of quadlinear and trilinear invariants in the free energy, coupling tilts and antipolar motions of the A and B sites to the polar mode, drives an avalanche-like transition to a non-centrosymmetric $Pna2_1$ symmetry in a wide range of magnetic perovskites with small tolerance factors - overcoming the above restrictions. We find that the $Pna2_1$ phase is especially favoured with tensile epitaxial strain, leading to an unexpected but technologically useful out-of-plane polarization. We use this mechanism to predict various novel multiferroics displaying interesting magnetoelectric properties with small polarization switching barriers.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05001
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Universal Polar Instability In Highly Orthorhombic Perovskites
Scott, Cameron A. M.
Bristowe, Nicholas C.
Materials Science
The design of novel multiferroic ABO$_3$ perovskites is complicated by the presence of necessary magnetic cations and ubiquitous antiferrodistortive modes, both of which suppress polar distortions. Using first-principles simulations, we observe that the existence of quadlinear and trilinear invariants in the free energy, coupling tilts and antipolar motions of the A and B sites to the polar mode, drives an avalanche-like transition to a non-centrosymmetric $Pna2_1$ symmetry in a wide range of magnetic perovskites with small tolerance factors - overcoming the above restrictions. We find that the $Pna2_1$ phase is especially favoured with tensile epitaxial strain, leading to an unexpected but technologically useful out-of-plane polarization. We use this mechanism to predict various novel multiferroics displaying interesting magnetoelectric properties with small polarization switching barriers.
title Universal Polar Instability In Highly Orthorhombic Perovskites
topic Materials Science
url https://arxiv.org/abs/2406.05001