文章基本信息

标题：Structural Instability of Epitaxial (001) BiFeO3 Thin Films under Tensile Strain
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作者：Zhen Fan ; John Wang ; Michael B. Sullivan 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：4
期号：1
DOI：10.1038/srep04631
语种：English
出版社：Springer Nature
摘要：We explore BiFeO₃ under tensile strain using first-principles calculations. We find that the actual structures are more complex than what had been previously thought, and that there is a strong shear deformation type structural instability which modifies the properties. Specifically, we find that normal tensile strain leads to structural instabilities with a large induced shear deformation in (001) BiFeO₃ thin films. These induced shear deformations in (001) BiFeO₃ thin films under tension stabilize the (001) BiFeO₃ thin films and lead to C c and I ma2 phases that are more stable than the P mc2₁ phase at high tensile strain. The induced shear deformation shifts the C c to I ma2 phase transition towards lower tensile strain region (~1% less), prevents monoclinic tilt and oxygen octahedral tilts, and increases the ferroelectric polarization. The induced shear deformation also strongly affects the electronic structure. The results are discussed in relation to growth of BiFeO₃ thin films on cubic and tetragonal substrates involving high levels of tensile strain.