Polarity compensation in ultra-thin films of complex oxides: The case of a perovskite nickelate

S. Middey, P. Rivero, D. Meyers, M. Kareev, X. Liu, Y. Cao, J. W. Freeland, S. Barraza-Lopez, J. Chakhalian

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Abstract

We address the fundamental issue of growth of perovskite ultra-thin films under the condition of a strong polar mismatch at the heterointerface exemplified by the growth of a correlated metal LaNiO3 on the band insulator SrTiO3 along the pseudo cubic [111] direction. While in general the metallic LaNiO3 film can effectively screen this polarity mismatch, we establish that in the ultra-thin limit, films are insulating in nature and require additional chemical and structural reconstruction to compensate for such mismatch. A combination of in-situ reflection high-energy electron diffraction recorded during the growth, X-ray diffraction, and synchrotron based resonant X-ray spectroscopy reveal the formation of a chemical phase La2Ni2O5 (Ni2+) for a few unit-cell thick films. First-principles layer-resolved calculations of the potential energy across the nominal LaNiO3/SrTiO3 interface confirm that the oxygen vacancies can efficiently reduce the electric field at the interface.

Original languageEnglish (US)
Article number6819
JournalScientific reports
Volume4
DOIs
StatePublished - Oct 29 2014

All Science Journal Classification (ASJC) codes

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    Middey, S., Rivero, P., Meyers, D., Kareev, M., Liu, X., Cao, Y., Freeland, J. W., Barraza-Lopez, S., & Chakhalian, J. (2014). Polarity compensation in ultra-thin films of complex oxides: The case of a perovskite nickelate. Scientific reports, 4, [6819]. https://doi.org/10.1038/srep06819