【摘 要】
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Oxygen vacancies (especially the Vc, which the oxygen vacancy is located along the c-axis) is thought to play an important role in ferroelectric fatigue of
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Oxygen vacancies (especially the Vc, which the oxygen vacancy is located along the c-axis) is thought to play an important role in ferroelectric fatigue of tetragonal PbTiO3 (PTO).The ab-biaxial strain effects on oxygen vacancies are studied by the first principle calculations.The oxygen vacancy performances in unstrained PTO are in accordance with the former studies.When the compressive strain was performed on PTO, an interesting phenomenon was found that there are two types polarization patterns in the vicinity of Vc: the "up-down" configuration (denoted by Vcud) and the "switchable" configuration (denoted by Vcsw), where in the latter configuration the orientations of the polarization above and below the vacancy plane are the same and, thus, does not affect the polarization magnitude.The Vcsw configuration is increasingly and finally more stable than the Vcud configuration when the compressive strain increase to-3%.Then we analyzed the causation of the appearance and the energy lowering for the Vcsw configuration for the compressive strain situation.
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