1. Carrier localization in perovskite nickelates from oxygen vacancies
- Author
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Shriram Ramanathan, David P. Landau, Yohannes Abate, Riccardo Comin, Jiarui Li, Hua Zhou, Karin M. Rabe, Fanny Rodolakis, John W. Freeland, Steven Bennett Hancock, Michele Kotiuga, Leonid P. Rokhinson, Ying Wang, Zhen Zhang, Neda Alsadat Aghamiri, Yifei Sun, Ronny Sutarto, Qi Wang, and Feizhou He
- Subjects
Superconductivity ,Multidisciplinary ,Materials science ,Condensed matter physics ,Oxide ,chemistry.chemical_element ,Heterojunction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Crystallographic defect ,Oxygen ,chemistry.chemical_compound ,chemistry ,Crystal field theory ,Electrical resistivity and conductivity ,0103 physical sciences ,Physical Sciences ,010306 general physics ,0210 nano-technology ,Perovskite (structure) - Abstract
Point defects, such as oxygen vacancies, control the physical properties of complex oxides, relevant in active areas of research from superconductivity to resistive memory to catalysis. In most oxide semiconductors, electrons that are associated with oxygen vacancies occupy the conduction band, leading to an increase in the electrical conductivity. Here we demonstrate, in contrast, that in the correlated-electron perovskite rare-earth nickelates, RNiO(3) (R is a rare-earth element such as Sm or Nd), electrons associated with oxygen vacancies strongly localize, leading to a dramatic decrease in the electrical conductivity by several orders of magnitude. This unusual behavior is found to stem from the combination of crystal field splitting and filling-controlled Mott–Hubbard electron–electron correlations in the Ni 3d orbitals. Furthermore, we show the distribution of oxygen vacancies in NdNiO(3) can be controlled via an electric field, leading to analog resistance switching behavior. This study demonstrates the potential of nickelates as testbeds to better understand emergent physics in oxide heterostructures as well as candidate systems in the emerging fields of artificial intelligence.
- Published
- 2019