Dimensionality-induced insulator-metal crossover in layered nickelates La{sub n+1}Ni{sub n}O{sub 2n+2} (n = 2, 3, and ∞)
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)
- Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Department of physics, Fudan University, Shanghai 200433 (China)
- Beijing Computational Science Research Center, Beijing 100084 (China)
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei 230026 (China)
Low-valence layered nickelates are a structural analog to the superconducting cuprates and possess interesting properties. In this work, we have systematically studied the electronic structure of La{sub n+1}Ni{sub n}O{sub 2n+2} using first-principles calculations. Our results reveal that the Ni-3d 3z{sup 2} − r{sup 2} orbital state is active and evolves from discrete molecular levels to a continuous solid band and its filling varies as the dimensionality (or n) increases. The two-dimensional (2D) La{sub 3}Ni{sub 2}O{sub 6} and La{sub 4}Ni{sub 3}O{sub 8} are thus found to have a molecular insulating state. In contrast, the 3D LaNiO{sub 2} is metallic and its 3z{sup 2} − r{sup 2} band surprisingly becomes 3D due to the Ni-La hybridization, and the La-5d xy orbital also forms a 2D metallic band. Therefore, La{sub n+1}Ni{sub n}O{sub 2n+2} is a dimensionality-controlled insulator-metal crossover system.
- OSTI ID:
- 22253040
- Journal Information:
- AIP Advances, Vol. 4, Issue 4; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
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