Nature of the metal-insulator transition in few-unit-cell-thick LaNiO3 films

Abstract

The nature of the metal insulator transition in thin films and superlattices of LaNiO3 with only 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 in the ultrathin films. Here we report results obtained for near-ideal LaNiO3 films with different thicknesses and terminations grown by atomic layer-by-layer laser molecular beam epitaxy on LaAlO3 substrates. We find that the room-temperature metallic behavior persists until the film thickness is reduced to an unprecedentedly small 1.5 unit cells (NiO2 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.

References in corpus (14)

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• Dimensionality Control of Electronic Phase Transitions in Nickel-Oxide Superlattices
• Metal-insulator transition in ultrathin LaNiO3 films
• Quantifying octahedral rotations in strained perovskite oxide films
• Orbital reflectometry
• Quantum confinement of Mott electrons in ultrathin LaNiO3/LaAlO3 superlattice
• Strain and composition dependence of the orbital polarization in nickelate superlattices
• Theory of the magnetic and metal-insulator transitions in RNiO3 bulk and layered structures
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• Influence of quantum confinement and strain on orbital polarization of four-layer LaNiO${}_3$ superlattices: a DFT+DMFT study
• Effect of charge doping on the electronic structure, orbital polarization, and structural distortion in nickelate superlattice
• Oxygen vacancy induced room temperature metal-insulator transition in nickelates films and its potential application in photovoltaics

Cited by in corpus (14)

• Flat bands promoted by Hund's rule coupling in the candidate double-layer high-temperature superconductor La${}_3$Ni${}_2$O${}_7$
• Probing Emergent Surface and Interfacial Properties in Complex Oxides via in situ X-ray Photoelectron Spectroscopy
• Oxygen vacancy induced site-selective mott transition in lanio3
• Two-dimensional type-II Dirac fermions in a LaAlO3/LaNiO3/LaAlO3 quantum well
• Cation spin and superexchange interaction in oxide materials below and above spin crossover under high pressure
• Anisotropy of electronic correlations: On the applicability of local theories to layered materials
• Gigantic-oxidative atomic-layer-by-layer epitaxy for artificially designed complex oxides
• A laser-ARPES study of LaNiO3 thin films grown by sputter deposition
• Zoology of spin and orbital fluctuations in ultrathin oxide films
• Epitaxially strained ultrathin LaNiO${}_3$/LaAlO${}_3$ and LaNiO${}_3$/SrTiO${}_3$ superlattices: a density functional theory + $U$ study
• Interplay between electron correlations, magnetic state, and structural confinement in LaNiO3 ultrathin films
• Emergent phenomena at oxide interfaces studied with standing-wave photoelectron spectroscopy
• Layer controlled orbital selective Mott transition in monolayer nickelate
• Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V2O3 Films