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Title: Dimensionality-induced insulator-metal crossover in layered nickelates La{sub n+1}Ni{sub n}O{sub 2n+2} (n = 2, 3, and ∞)

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.
Authors:
; ;  [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [5]
  1. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)
  2. Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Department of physics, Fudan University, Shanghai 200433 (China)
  3. (China)
  4. Beijing Computational Science Research Center, Beijing 100084 (China)
  5. Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei 230026 (China)
Publication Date:
OSTI Identifier:
22253040
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 4; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ELECTRONIC STRUCTURE; HYBRIDIZATION; METALS; NICKELATES; SOLIDS