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Title: Effects of charge fluctuation and charge regulation on the phase transitions in stoichiometric VO2
Abstract

Detailed electrical and photoemission studies were carried out to probe the chemical nature of the insulating ground state of VO2, whose properties have been an issue for accurate prediction by common theoretical probes. The effects of a systematic modulation of oxygen over-stoichiometry of VO2from 1.86 to 2.44 on the band structure and insulator–metal transitions are presented for the first time. Results offer a different perspective on the temperature- and doping-induced IMT process. They suggest that charge fluctuation in the metallic phase of intrinsic VO2results in the formation of eand h+pairs that lead to delocalized polaronic V3+and V5+cation states. The metal-to-insulator transition is linked to the cooperative effects of changes in the V–O bond length, localization of V3+electrons at V5+sites, which results in the formation of V4+–V4+dimers, and removal of$$\pi^{*}$$πscreening electrons. It is shown that the nature of phase transitions is linked to the lattice V3+/V5+concentrations of stoichiometric VO2and that electronic transitions are regulated by the interplay between charge fluctuation, charge redistribution, and structural transition.

 
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Award ID(s):
1709649
NSF-PAR ID:
10198016
Author(s) / Creator(s):
; ;
Publisher / Repository:
Nature Publishing Group
Date Published:
Journal Name:
Scientific Reports
Volume:
10
Issue:
1
ISSN:
2045-2322
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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