Photoemission evidence for a Mott-Hubbard metal-insulator transition in VO${}_2$

Abstract

The temperature ($T$) dependent metal-insulator transition (MIT) in VO${}_2$ is investigated using bulk sensitive hard x-ray ($\sim$ 8 keV) valence band, core level, and V 2$p-3d$ resonant photoemission spectroscopy (PES). The valence band and core level spectra are compared with full-multiplet cluster model calculations including a coherent screening channel. Across the MIT, V 3$d$ spectral weight transfer from the coherent ($d^1\underline{\text{C}}$ final) states at Fermi level to the incoherent ($d^0+d^1\underline{\text{L}}$ final) states, corresponding to the lower Hubbard band, lead to gap-formation. The spectral shape changes in V 1$s$ and V 2$p$ core levels as well as the valence band are nicely reproduced from a cluster model calculations, providing electronic structure parameters. Resonant-PES finds that the $d^1\underline{\text{L}}$ states resonate across the V 2$p-3d$ threshold in addition to the $d^0$ and $d^1\underline{\text{C}}$ states. The results support a Mott-Hubbard transition picture for the first order MIT in VO${}_2$.

6 pages, 3 figures. to be published in Phys. Rev. B

References in corpus (6)

• Mott transition in VO2 revealed by infrared spectroscopy and nano-imaging
• Evidence for a Structurally-driven Insulator-to-metal Transition in VO2: a View from the Ultrafast Timescale
• Orbital-assisted metal-insulator transition in VO${}_2$
• Bulk screening in core level photoemission from Mott-Hubbard and Charge-Transfer systems
• Theory of Core-Level Photoemission and the X-ray Edge Singularity Across the Mott Transition
• Cluster model calculations with non-local screening channels of metallic and insulating VO2

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• Combined GW and dynamical mean field theory: Dynamical screening effects in transition metal oxides
• Effective band-structure in the insulating phase versus strong dynamical correlations in metallic VO2
• The insulating phases of vanadium dioxide are Mott-Hubbard insulators
• Photoemission evidence for crossover from Peierls-like to Mott-like transition in highly strained VO${}_2$
• Electron Correlation driven Metal-Insulator transition in Strained and Disordered VO2 films
• Satellites in the Ti~1$s$ core level spectra of SrTiO${}_3$ and TiO${}_2$
• Occupation switching of $d$ orbitals probed via hyperfine interactions in vanadium dioxide
• Atomic multiplet and charge-transfer screening effects in 1$s$ and 2$p$ core-level X-ray photoelectron spectra of early 3$d$ transition-metal oxides
• Nature of the photo-induced metallic state in monoclinic VO${}_2$
• Effective Band Structure of Correlated Materials - The Case of VO2
• Balancing orbital effects and onsite Coulomb repulsion through Na modulations in NaxVO2