Orbital electronic occupation effect on metal–insulator transition in TixV1−xO2. (1st August 2017)

• Record Type: Journal Article
• Authors: Huang, Kang; Meng, Yifan; Xu, XiaoFeng; Chen, Pingping; Lu, Aijiang; Li, Hui; Wu, Binhe; Wang, Chunrui; Chen, Xiaoshuang
• Is Part Of: Journal of physics. Volume 29:Number 35(2017)
• Publication Date: 2017-08-01
• Subjects: TixV1−xO2 thin films -- orbital electronic occupation -- TMIT; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa7707
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: A series of Ti x V1− x O2 (0% ⩽ x ⩽ 4.48%) thin films on c -plane sapphire substrates have been fabricated by co-sputtering oxidation solutions, and the metal–insulator transition temperature ( T MIT ) of Ti x V1− x O2 films rises monotonically at the rate of 1.64 K/at.% Ti. The x-ray diffraction measurement results show that, after Ti 4+ ion doping, the rutile structure expands along the c r axis while shrinking along the a r and b r axis simultaneously. It makes the V–O bond length shorter, which is believed to upshift the π * orbitals. The rising of π * orbitals in Ti-doped VO2 has been illustrated by ultraviolet–infrared spectroscopy and first-principles calculation. With the Ti 4+ ion doping concentration increasing, the energy levels of π * orbitals are elevated and the electronic occupation of π * orbitals decreases, which weakens the shielding for the strong electron–electron correlations in the d|| orbital and result in the T MIT rising. The research reveals that the T MIT of VO2 can be effected by the electronic occupancy of π * orbitals in a rutile state, which is helpful for developing VO2 -based thermal devices.