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Distinct electronic structure of the electrolyte gate-induced conducting phase in vanadium dioxide revealed by high-energy photoelectron spectroscopy

Karel J, Violbarbosa CE, Kiss J, Jeong J, Aetukuri N, Samant MG, Kozina X, Ikenaga E, Fecher GH, Felser C, Parkin SSP (2014)

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Publication Type: Journal article

Publication year: 2014

Journal

Book Volume: 8

Pages Range: 5784-5789

Journal Issue: 6

DOI: 10.1021/nn501724q

Abstract

The development of new phases of matter at oxide interfaces and surfaces by extrinsic electric fields is of considerable significance both scientifically and technologically. Vanadium dioxide (VO2), a strongly correlated material, exhibits a temperature-driven metal-to-insulator transition, which is accompanied by a structural transformation from rutile (high-temperature metallic phase) to monoclinic (low-temperature insulator phase). Recently, it was discovered that a low-temperature conducting state emerges in VO2 thin films upon gating with a liquid electrolyte. Using photoemission spectroscopy measurements of the core and valence band states of electrolyte-gated VO2 thin films, we show that electronic features in the gate-induced conducting phase are distinct from those of the temperature-induced rutile metallic phase. Moreover, polarization-dependent measurements reveal that the V 3d orbital ordering, which is characteristic of the monoclinic insulating phase, is partially preserved in the gate-induced metallic phase, whereas the thermally induced metallic phase displays no such orbital ordering. Angle-dependent measurements show that the electronic structure of the gate-induced metallic phase persists to a depth of at least ∼40 Å, the escape depth of the high-energy photoexcited electrons used here. The distinct electronic structures of the gate-induced and thermally induced metallic phases in VO2 thin films reflect the distinct mechanisms by which these states originate. The electronic characteristics of the gate-induced metallic state are consistent with the formation of oxygen vacancies from electrolyte gating. © 2014 American Chemical Society.

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How to cite

APA:

Karel, J., Violbarbosa, C.E., Kiss, J., Jeong, J., Aetukuri, N., Samant, M.G.,... Parkin, S.S.P. (2014). Distinct electronic structure of the electrolyte gate-induced conducting phase in vanadium dioxide revealed by high-energy photoelectron spectroscopy. ACS nano, 8(6), 5784-5789. https://doi.org/10.1021/nn501724q

MLA:

Karel, Julie, et al. "Distinct electronic structure of the electrolyte gate-induced conducting phase in vanadium dioxide revealed by high-energy photoelectron spectroscopy." ACS nano 8.6 (2014): 5784-5789.

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