Title: Stabilization of Highly Polar ${\mathrm{BiFeO}}_3$ -like Structure: A New Interface Design Route for Enhanced Ferroelectricity in Artificial Perovskite Superlattices

Abstract

In ABO₃ perovskites, oxygen octahedron rotations are common structural distortions that can promote large ferroelectricity in BiFeO₃ with an R3c structure [1] but suppress ferroelectricity in CaTiO₃ with a Pbnm symmetry [2]. For many CaTiO3-like perovskites, the BiFeO₃ structure is a metastable phase. Here, we report the stabilization of the highly polar BiFeO₃-like phase of CaTiO₃ in a BaTiO₃/CaTiO₃ superlattice grown on a SrTiO₃ substrate. The stabilization is realized by a reconstruction of oxygen octahedron rotations at the interface from the pattern of nonpolar bulk CaTiO₃ to a different pattern that is characteristic of a BiFeO₃ phase. The reconstruction is interpreted through a combination of amplitude-contrast sub-0.1-nm high-resolution transmission electron microscopy and first-principles theories of the structure, energetics, and polarization of the superlattice and its constituents. We further predict a number of new artificial ferroelectric materials demonstrating that nonpolar perovskites can be turned into ferroelectrics via this interface mechanism. Therefore, a large number of perovskites with the CaTiO₃ structure type, which include many magnetic representatives, are now good candidates as novel highly polar multiferroic materials [3].

Authors:

Wang, Hongwei; Wen, Jianguo; Miller, Dean J.; Zhou, Qibin; Chen, Mohan; Lee, Ho Nyung; Rabe, Karin M.; Wu, Xifan

Publication Date:

Mon Mar 14 00:00:00 EDT 2016

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Center for the Computational Design of Functional Layered Materials (CCDM)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1241453

Alternate Identifier(s):

OSTI ID: 1261345

Grant/Contract Number:  

SC0012575; AC02-05CH11231; AC02-06CH11357; AC05-00OR22725

Resource Type:

Published Article

Journal Name:

Physical Review. X

Additional Journal Information:

Journal Name: Physical Review. X Journal Volume: 6 Journal Issue: 1; Journal ID: ISSN 2160-3308

Publisher:

American Physical Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE