Chin. Phys. B ›› 2013, Vol. 22 ›› Issue (12): 127103-127103.doi: 10.1088/1674-1056/22/12/127103

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

In situ electronic structural study of VO2 thin film across the metal–insulator transition

伊明江·买买提, 阿布都艾则孜·阿布来提, 吴蕊, 王嘉鸥, 钱海杰, 奎热西·依布拉欣   

  1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2013-03-07 修回日期:2013-04-14 出版日期:2013-10-25 发布日期:2013-10-25
  • 基金资助:
    Project supported by the Natural Science Foundation of the Chinese Academy of Sciences (Grant No. H91G750Y21).

In situ electronic structural study of VO2 thin film across the metal–insulator transition

Emin Muhemmed (伊明江·买买提), Abduleziz Ablat (阿布都艾则孜·阿布来提), Wu Rui (吴蕊), Wang Jia-Ou (王嘉鸥), Qian Hai-Jie (钱海杰), Kurash Ibrahim (奎热西·依布拉欣)   

  1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-03-07 Revised:2013-04-14 Online:2013-10-25 Published:2013-10-25
  • Contact: Kurash Ibrahim E-mail:kurash@ihep.ac.cn
  • Supported by:
    Project supported by the Natural Science Foundation of the Chinese Academy of Sciences (Grant No. H91G750Y21).

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摘要： The in situ valence band photoemission spectrum (PES) and X-ray absorption spectrum (XAS) at V LⅡ-LⅢ edges of the VO2 thin film, which is prepared by pulsed laser deposition, are measured across the metal–insulator transition (MIT) temperature (TMIT=67 ℃). The spectra show evidence for changes in the electronic structure depending on temperature. Across the TMIT, pure V 3d characteristic d‖ and O 2p-V 3d hybridization characteristic πpd, σpd bands vary in binding energy position and density of state distributions. The XAS reveals a temperature-dependent reversible energy shift at the V LⅢ-edge. The PES and XAS results imply a synergetic energy position shift of occupied valence bands and unoccupied conduction band states across the phase transition. A joint inspection of the PES and XAS results shows that the MIT is not a one-step process, instead it is a process in which a semiconductor phase appears as an intermediate state. The final metallic phase from insulating state is reached through insulator–semiconductor, semiconductor–metal processes, and vice versa. The conventional MIT at around the TMIT=67 ℃ is actually a semiconductor–insulator transformation point.

关键词: vanadium dioxide, metal–, insulator transition, electronic structure, photoemission spectroscopy

Abstract: The in situ valence band photoemission spectrum (PES) and X-ray absorption spectrum (XAS) at V LⅡ-LⅢ edges of the VO2 thin film, which is prepared by pulsed laser deposition, are measured across the metal–insulator transition (MIT) temperature (TMIT=67 ℃). The spectra show evidence for changes in the electronic structure depending on temperature. Across the TMIT, pure V 3d characteristic d‖ and O 2p-V 3d hybridization characteristic πpd, σpd bands vary in binding energy position and density of state distributions. The XAS reveals a temperature-dependent reversible energy shift at the V LⅢ-edge. The PES and XAS results imply a synergetic energy position shift of occupied valence bands and unoccupied conduction band states across the phase transition. A joint inspection of the PES and XAS results shows that the MIT is not a one-step process, instead it is a process in which a semiconductor phase appears as an intermediate state. The final metallic phase from insulating state is reached through insulator–semiconductor, semiconductor–metal processes, and vice versa. The conventional MIT at around the TMIT=67 ℃ is actually a semiconductor–insulator transformation point.

Key words: vanadium dioxide, metal–insulator transition, electronic structure, photoemission spectroscopy

中图分类号:  (Metal-insulator transitions and other electronic transitions)

  • 71.30.+h
79.60.-i (Photoemission and photoelectron spectra) 78.70.Dm (X-ray absorption spectra) 73.20.At (Surface states, band structure, electron density of states)