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arXiv · 1108.3326

Interplay of epitaxial strain and rotations in PbTiO$_3$/PbZrO$_3$ superlattices from first principles

Jeroen L. Blok·Karin M. Rabe·David Vanderbilt·Dave H. A. Blank·Guus Rijnders
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Abstract

We present first-principles calculations of the structural phase behavior of the [1:1] \pzta\ superlattice and the \ptoa\ and \pzoa\ parent compounds as a function of in-plane epitaxial strain. A symmetry analysis is used to identify the phases and clarify how they arise from an interplay between different kinds of structural distortions, including out-of-plane and in-plane polar modes, rotation of oxygen octahedra around out-of-plane or in-plane axes, and an anti-polar mode. Symmetry-allowed intermode couplings are identified and used to elucidate the nature of the observed phase transitions. For the minimum-period [1:1] \pzta\ superlattice, we identify a sequence of three transitions that occur as the in-plane lattice constant is increased. All four of the phases involve substantial oxygen octahedral rotations, and an antipolar distortion is important in the high-tensile-strain phase. Inclusion of these distortions is found to be crucial for an accurate determination of the phase boundaries.

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Jeroen L. Blok, Karin M. Rabe, David Vanderbilt, Dave H. A. Blank, Guus Rijnders. 2011-10-12. Interplay of epitaxial strain and rotations in PbTiO$_3$/PbZrO$_3$ superlattices from first principles. https://doi.org/10.1103/physrevb.84.205413

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