Nature of the metal-insulator transition in few-unit-cell-thick LaNiO 3 films.

Autor:	Golalikhani M; Department of Physics, Temple University, Philadelphia, PA, 19122, USA. maryam@temple.edu., Lei Q; Department of Physics, Temple University, Philadelphia, PA, 19122, USA., Chandrasena RU; Department of Physics, Temple University, Philadelphia, PA, 19122, USA.; Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA., Kasaei L; Department of Physics, Temple University, Philadelphia, PA, 19122, USA., Park H; Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA.; Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA., Bai J; National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA., Orgiani P; CNR-SPIN, UOS Salerno, 84084, Fisciano, Italy.; CNR-IOM, TASC Laboratory in Area Science Park, 34139, Trieste, Italy., Ciston J; National Center for Electron Microscopy Facility, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA., Sterbinsky GE; Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA., Arena DA; Department of Physics, University of South Florida, Tampa, FL, 33620, USA., Shafer P; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA., Arenholz E; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA., Davidson BA; Department of Physics, Temple University, Philadelphia, PA, 19122, USA.; CNR-IOM, TASC Laboratory in Area Science Park, 34139, Trieste, Italy., Millis AJ; Department of Physics, Columbia University, New York, NY, 10027, USA.; Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, 10010, USA., Gray AX; Department of Physics, Temple University, Philadelphia, PA, 19122, USA.; Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA., Xi XX; Department of Physics, Temple University, Philadelphia, PA, 19122, USA. xiaoxing@temple.edu.; Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA. xiaoxing@temple.edu.
Jazyk:	angličtina
Zdroj:	Nature communications [Nat Commun] 2018 Jun 07; Vol. 9 (1), pp. 2206. Date of Electronic Publication: 2018 Jun 07.
DOI:	10.1038/s41467-018-04546-5
Abstrakt:	The nature of the metal-insulator transition in thin films and superlattices of LaNiO 3 only a few unit cells in thickness remains elusive despite tremendous effort. Quantum confinement and epitaxial strain have been evoked as the mechanisms, although other factors such as growth-induced disorder, cation non-stoichiometry, oxygen vacancies, and substrate-film interface quality may also affect the observable properties of ultrathin films. Here we report results obtained for near-ideal LaNiO 3 films with different thicknesses and terminations grown by atomic layer-by-layer laser molecular beam epitaxy on LaAlO 3 substrates. We find that the room-temperature metallic behavior persists until the film thickness is reduced to an unprecedentedly small 1.5 unit cells (NiO 2 termination). Electronic structure measurements using X-ray absorption spectroscopy and first-principles calculation suggest that oxygen vacancies existing in the films also contribute to the metal-insulator transition.
Databáze:	MEDLINE
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