Photoinduced physical-properties switching of photochromic rare-earth metal oxyhydrides thin films

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02596
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Shimizu Ryota 東京工業大学, 物質理工学院, 准教授 (70611953)
• Co-Investigator(Kenkyū-buntansha): 関場 大一郎 筑波大学, 数理物質系, 講師 (20396807)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 薄膜物性 / 複合アニオン化合物 / 光物性 / 電子物性 / 電気化学

Outline of Final Research Achievements

In this study, we demonstrated repeatable photoinduced insulator-to-metal transition of rare-earth metal oxyhydrides using ultraviolet laser illumination for the first time. This permanent photoconductivity can be switched to the original insulating states by thermal annealing in argon atmosphere at 120oC for 2h. To investigate this photoinduced metallization, we performed high-resolution measurements including compositional and structural analysis based on sparse modeling technique, and obtained reliable structural models for theoretical calculations. The theoretical calculations reveals that excess hydrogen in the films can generate itinerant photocarriers, leading to metallic conduction. Thus, we succeeded in the exotic functions based on hydrogen in rare-earth metal oxyhydrides.

Free Research Field

薄膜物性

Academic Significance and Societal Importance of the Research Achievements

光による絶縁体から金属へのスイッチングを繰り返し行った例は、どの物質においても世界で初めての成果である(プレスリリース済み)。未発表ではあるが、任意のタイミングにおける絶縁化の時間短縮にも成功しており、スマートウィンドウや光センサ・光メモリ応用につながる画期的な成果である。