Stabilization of Highly PolarBiFeO3-like Structure: A New Interface Design Route for Enhanced Ferroelectricity in Artificial Perovskite Superlattices
Miller, Dean J.
Lee, Ho Nyung
Rabe, Karin M.
Permanent link to this recordhttp://hdl.handle.net/20.500.12613/8778
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AbstractIn ABO3 perovskites, oxygen octahedron rotations are common structural distortions that can promote large ferroelectricity in BiFeO3 with an R3c structure  but suppress ferroelectricity in CaTiO3 with a Pbnm symmetry . 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 .
Citation to related workAmerican Physical Society
Has partPhysical Review X, Vol. 6
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