文章基本信息

标题：Polarity compensation in ultra-thin films of complex oxides: The case of a perovskite nickelate
本地全文：下载
作者：S. Middey ; P. Rivero ; D. Meyers 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/srep06819
语种：English
出版社：Springer Nature
摘要：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.