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arXiv · 1006.5146

Polarity-induced oxygen vacancies at LaAlO3|SrTiO3 interfaces

Zhicheng Zhong·P. X. Xu·Paul J. Kelly
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Abstract

Using first-principles density functional theory calculations, we find a strong position and thickness dependence of the formation energy of oxygen vacancies in LaAlO3|SrTiO3 (LAO|STO) multilayers and interpret this with an analytical capacitor model. Oxygen vacancies are preferentially formed at p-type SrO|AlO2 rather than at n-type LaO|TiO2 interfaces; the excess electrons introduced by the oxygen vacancies reduce their energy by moving to the n-type interface. This asymmetric behavior makes an important contribution to the conducting (insulating) nature of n-type (p-type) interfaces while providing a natural explanation for the failure to detect evidence for the polar catastrophe in the form of core level shifts.

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Zhicheng Zhong, P. X. Xu, Paul J. Kelly. 2010-06-26. Polarity-induced oxygen vacancies at LaAlO3|SrTiO3 interfaces. https://doi.org/10.1103/physrevb.82.165127

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