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https://doi.org/10.1039/c7nr00742f
Title: | Investigation of the metal-insulator transition in NdNiO3 films by site-selective X-ray absorption spectroscopy | Authors: | Palina, N Wang, L Dash, S Yu, X Breese, M.B.H Wang, J Rusydi, A |
Keywords: | Deposition Electronic properties Excitons Metal insulator boundaries Nickel Oxide films Pulsed laser deposition Semiconductor insulator boundaries Temperature Thin films X ray absorption near edge structure spectroscopy X ray absorption spectroscopy Crystallographic structure Disproportionations Insulating phase Multifunctional oxides Orbital occupancy Possible mechanisms Temperature-dependent resistivity X-ray absorption near-edge structure Metal insulator transition |
Issue Date: | 2017 | Publisher: | Royal Society of Chemistry | Citation: | Palina, N, Wang, L, Dash, S, Yu, X, Breese, M.B.H, Wang, J, Rusydi, A (2017). Investigation of the metal-insulator transition in NdNiO3 films by site-selective X-ray absorption spectroscopy. Nanoscale 9 (18) : 6094-6102. ScholarBank@NUS Repository. https://doi.org/10.1039/c7nr00742f | Abstract: | In this work, multifunctional oxide NdNiO3 (NNO) thin films grown on a SrTiO3 (STO) substrate using pulsed-laser deposition are studied. Temperature dependent resistivity measurements revealed that NNO/STO samples exhibit a sharp thickness dependent metal-insulator transition (MIT) over a range of 150-200 K. It is known that the electronic properties of correlated oxides are extremely complex and sensitive to changes in orbital occupancy. To evaluate the changes in the electronic and/or crystallographic structure responsible for the MIT, a site-selective (O, Ni and Nd) X-ray absorption near edge structure (XANES) analysis is performed above and below the transition temperature. Analysis of XANES spectra suggests that: (i) in NNO films nominally trivalent Ni ions exhibit multiple valency (bond disproportionation), (ii) intermetallic hybridization plays an important role, (iii) the presence of strong O 2p-O 2p hole correlation at low temperature results in the opening of the p-p gap and (iv) the valency of Nd ions matches well with that of Nd3+. For NNO films exhibiting a sharp MIT, Ni 3d electron localization and concurrent existence of Ni 3d8 and Ni 3d8L2 states are responsible for the observed transition. At temperatures below the MIT the O 2p-O 2p hole correlation is strong enough to split the O 2p band stabilizing insulating phase. Temperature and thickness dependent differences observed in the site-selective XANES data are discussed in terms of possible mechanisms for the MIT (negative charge-transfer type). © The Royal Society of Chemistry 2017. | Source Title: | Nanoscale | URI: | https://scholarbank.nus.edu.sg/handle/10635/174426 | ISSN: | 2040-3364 | DOI: | 10.1039/c7nr00742f |
Appears in Collections: | Elements Staff Publications |
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