Interplay of epitaxial strain and rotations in PbTiO3/PbZrO3 superlattices from first principles

Article

关键词: AUGMENTED-WAVE METHOD;    THIN-FILMS;    ANTIFERROELECTRIC PBZRO3;    BOUNDARY-CONDITIONS;    PHASE-TRANSITIONS;    1ST-PRINCIPLES;    POLARIZATION;    DIFFRACTION;    PEROVSKITES;    DYNAMICS;   

DOI  :  10.1103/PhysRevB.84.205413

来源: SCIE

【 摘 要 】

We present first-principles calculations of the structural phase behavior of the [1:1] PbTiO3/PbZrO3 superlattice and the PbTiO3 and PbZrO3 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 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 antipolar mode. Symmetry-allowed intermode couplings are identified and used to elucidate the nature of the observed phase transitions. For the minimum-period [1:1] PbTiO3/PbZrO3 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.

【 授权许可】

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