Establishment of photocarrier injection method by which electronic properties of strongly correlated materials can be controlled.

2013 Fiscal Year Final Research Report

• Project/Area Number: 23540410
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Okayama University
• Principal Investigator: MURAOKA Yuji 岡山大学, 自然科学研究科, 准教授 (10323635)
• Co-Investigator(Renkei-kenkyūsha): YOKOYA Takayoshi 岡山大学, 大学院・自然科学研究科, 教授 (90311646)
• Project Period (FY): 2011 – 2013
• Keywords: 強相関系 / 界面

Research Abstract

Photocarrier injection to transition metal oxide thin films and the electronic states of the films are investigated. We have observed an insulator-to-metal transition of VO2 thin films induced by soft X-ray irradiation. Electron carriers are injected into the V 3d band upon soft-X ray irradiation. We propose a simple model where the transition is driven by desorption of oxygen from the films. The Fermi surface topology of a metallic VO2 thin film is studied by angle-resolved photoemission spectroscopy (ARPES) and the nesting vector is found to be present. Near topmost layer of CrO2 thin films are revealed to be metallic by surface sensitive PES. Also, a single-phase TaO2 thin film and spinodally decomposed (V,Ti)O2 thin film are developed.

Research Products

• [Journal Article] Persistent insulator to metal transition of a VO2 thin film by soft x-ray irradiation (2014)
  • Author(s): Y. Muraoka, H. Nagao, S. Katayama, T. Wakita, M. Hirai, T. Yokoya, H. Kumigashira, and M. Oshima
  • Journal Title: Jpn. J. Appl. Phys Volume: 53 Pages: 05FB09/1-4
  • DOI: 10.7567
  • Peer Reviewed
• [Journal Article] Ultrafast photoinduced transition of an insulating VO2 thin film into a nonrutile metallic state (2014)
  • Author(s): R. Yoshida, T. Yamamoto, Y. Ishida, H. Nagao, T. Otsuka, K. Saeki, Y. Muraoka, R. Eguchi, K. Ishizaka, T. Kiss, S. Watanabe, T. Kanai, J. Itatani, and S. Shin
  • Journal Title: Phys. Rev. B Volume: (in press)
  • DOI: 10.1103
  • Peer Reviewed
• [Journal Article] Spinodal decomposition in the TiO2-VO2 system (2013)
  • Author(s): Z. Hiroi, H. Hayamizu, T. Yoshida, Y. Muraoka, Y. Okamoto, J. Yamaura, and Y. Ueda
  • Journal Title: Chem. Mater Volume: 25 Pages: 2202-2210
  • DOI: 10.1021
  • Peer Reviewed
• [Journal Article] Surface physical property of the CrO2 thin films prepared using a closed chemical vapor deposition method, Materials Research Society online Proceedings library (2011)
  • Author(s): Y. Muraoka, S. Yoshida, T. Wakita, M. Hirai, T. Yokoya
  • Journal Title: Function Metal-Oxide Nanostructures Volume: 1406
  • Peer Reviewed
• [Presentation] VO2薄膜における軟X線誘起絶縁体金属転移 (2014)
  • Author(s): 村岡祐治, 長尾浩樹, 脇田高徳, 横谷尚睦, 組頭広志, 尾嶋正治
  • Organizer: 放射光科学による革新的イノベーションワークショップ
  • Place of Presentation: 岡山大学津島キャンパス
  • Year and Date: 2014-03-14
• [Presentation] Spin-resolved Photoemission Spectroscopy of CrO2 thin films (2014)
  • Author(s): Y. Muraoka, M. Sunagawa, A. Mizutani, K. Miyamoto and T. Okuda
  • Organizer: The 18th Hiroshima International Symposium on Synchrotron Radiation
  • Place of Presentation: Hiroshima University
  • Year and Date: 2014-03-06
• [Presentation] Photocarrier injection to VO2 thin film (2013)
  • Author(s): Y. Muraoka, T. Wakita, and T. Yokoya
  • Organizer: 2013 JSAP-MRS joint symposia
  • Place of Presentation: 同志社大学京田辺キャンパス
  • Year and Date: 2013-09-17
• [Presentation] Photo-induced insulator to metal transition for VO2 thin films (2013)
  • Author(s): Y. Muraoka, H. Nagao, T. Wakita and T. Yokoya
  • Organizer: The 17th Hiroshima International Symposium on Synchrotron Radiation
  • Place of Presentation: Hiroshima University
  • Year and Date: 2013-02-28
• [Presentation] Surface physical property of the CrO2 thin films (2012)
  • Author(s): Y. Muraoka, S. Yoshida, T. Wakita, M. Hirai, T. Yokoya
  • Organizer: International Symposium on Physics and Chemistry of Novel Superconductors and Related Materials
  • Place of Presentation: 岡山大学
  • Year and Date: 2012-10-02
• [Presentation] VO2薄膜における光誘起絶縁体-金属転移とその電子状態の観測 (2012)
  • Author(s): 村岡祐治, 長尾浩樹, 脇田高徳, 横谷尚睦, 組頭広志, 尾嶋正治
  • Organizer: 日本物理学会2012年秋季大会
  • Place of Presentation: 横浜国立大学常盤台キャンパス
  • Year and Date: 2012-09-20
• [Presentation] Effectiveness of a closed CVD method for preparation of CrO2 thin films (2012)
  • Author(s): Y. Muraoka, S. Yoshida, T. Wakita, T. Yokoya, H. Kumugashira, and M. Oshima
  • Organizer: 2012年秋季第73回応用物理学会学術講演会
  • Place of Presentation: 愛媛大学城北地区/松山大学文京キャンパス
  • Year and Date: 2012-09-12
• [Presentation] CrO2単結晶薄膜作製における閉鎖系化学気相法の利点, 応用物理学会中国四国支部, 日本物理学会中国支部, 四国支部 (2012)
  • Author(s): 村岡祐治, 吉田祥, 脇田高徳, 横谷尚睦
  • Organizer: 2012年度支部学術講演会
  • Place of Presentation: 山口大学常盤キャンパス
  • Year and Date: 2012-07-28
• [Presentation] VO2薄膜における放射光誘起絶縁体金属転移, 応用物理学会中国四国支部, 日本物理学会中国支部, 四国支部 (2012)
  • Author(s): 村岡祐治, 長尾浩樹, 脇田高徳, 横谷尚睦
  • Organizer: 2012年度支部学術講演会
  • Place of Presentation: 山口大学常盤キャンパス
  • Year and Date: 2012-07-28
• [Presentation] 閉鎖系化学気相法により作製したCrO2薄膜の表面特性 (2012)
  • Author(s): 村岡祐治, 吉田祥, 脇田高徳, 平井正明, 横谷尚睦
  • Organizer: 日本物理学会第67回年次大会
  • Place of Presentation: 関西学院大学西宮上ヶ原キャンパス
  • Year and Date: 2012-03-27
• [Presentation] CrO2薄膜の表面特性 (2012)
  • Author(s): 村岡祐治, 吉田祥, 脇田高徳, 平井正明, 横谷尚睦
  • Organizer: 2012年春季第59回応用物理学関係連合講演会
  • Place of Presentation: 早稲田大学早稲田キャンパス
  • Year and Date: 2012-03-17
• [Presentation] 光照射によるVO2薄膜への電子キャリア注入 (2012)
  • Author(s): 村岡祐治, 長尾浩樹, 大山卓郎, 脇田高徳, 平井正明, 横谷尚睦
  • Organizer: 2012年春季第59回応用物理学関係連合講演会
  • Place of Presentation: 早稲田大学早稲田キャンパス
  • Year and Date: 2012-03-17
• [Presentation] Metallic surface of the CrO2 thin films prepared using a closed chemical vapor deposition method (2012)
  • Author(s): Y. Muraoka, S. Yoshida, M. Hirai, T. Wakita and T. Yokoya
  • Organizer: The 16th Hiroshima International Symposium on Synchrotron Radiation
  • Place of Presentation: Hiroshima University
  • Year and Date: 2012-03-01
• [Presentation] Surface physical property of the CrO2 thin films prepared using a closed chemical vapor deposition method (2011)
  • Author(s): Y. Muraoka, S. Yoshida, T. Wakita, M. Hirai, and T. Yokoya
  • Organizer: 2011 Fall Meeting of the Materials Research Society
  • Place of Presentation: Hynes Convention Center, Boston, U.S.A
  • Year and Date: 2011-11-28
• [Presentation] 放射光照射によるVO2薄膜への電子キャリア注入 (2011)
  • Author(s): 村岡祐治, 長尾浩樹, 脇田高徳, 平井正明, 横谷尚睦, 室隆桂之, 為則雄祐
  • Organizer: 日本物理学会2011年秋季大会
  • Place of Presentation: 富山大学五福キャンパス
  • Year and Date: 2011-09-21
• [Presentation] Preparation of NbO2 thin films using a pulsed laser deposition method (2011)
  • Author(s): Y. Muraoka, Y. Fujimoto, C. Hiramatsu, T. Wakita, M. Hirai, T. Yokoya
  • Organizer: 2011年秋季第72回応用物理学会学術講演会
  • Place of Presentation: 山形大学小白川キャンパス
  • Year and Date: 2011-08-31
• [Presentation] VO2薄膜における放射光照射効果, 応用物理学会中国四国支部, 日本物理学会中国支部, 四国支部 (2011)
  • Author(s): 村岡祐治, 片山晋輔, 長尾浩樹, 脇田高徳, 平井正明, 横谷尚睦, 室隆桂之, 泉雄大, 為則雄祐
  • Organizer: 2011年度支部学術講演会
  • Place of Presentation: 鳥取大学鳥取キャンパス
  • Year and Date: 2011-07-30
• [Presentation] 尾嶋正治VO2薄膜の金属相フェルミ面ネスティング (0)
  • Author(s): 村岡祐治, 長尾浩樹, 脇田高徳, 横谷尚睦, 組頭広志
  • Organizer: 日本物理学会, 2013年秋季大会
  • Place of Presentation: 徳島大学常三島キャンパス
  • Year and Date: 00000927
• [Remarks]
  • URL: http://film.rlss.okayama-u.ac.jp/~hakumaku/