Soft X-ray absorption spectroscopy measurement under operation of electric double layer transistor

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K20906
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: National Institutes for Quantum Science and Technology (2021-2022); High Energy Accelerator Research Organization (2020)
• Principal Investigator: Koji Horiba 国立研究開発法人量子科学技術研究開発機構, 関西光量子科学研究所 放射光科学研究センター, 上席研究員 (10415292)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 電気二重層トランジスタ / 転換可視蛍光収量 / オペランド軟X線吸収分光

Outline of Final Research Achievements

Recently, the electric double layer transistor (EDLT) method, in which an ionic liquid is coated on an oxide material and a carrier is injected into the oxide by applying an electric field, has been used with great success as a method for modulating physical properties and creating giant responses by carrier doping in strongly correlated oxides. Observation of the electronic state of this carrier-injected oxide is important for an intrinsic understanding of the property modulation mechanism. However, it has been difficult to observe the electronic state of the carrier storage layer because it is buried in the ionic liquid. In this study, we developed a new soft X-ray absorption spectroscopy with transmission configuration and succeeded in observing the electronic structure of oxides buried under ionic liquids.

Free Research Field

X線分光

Academic Significance and Societal Importance of the Research Achievements

近年、系に不純物を添加しない純粋なキャリアドープ手法として、イオン液体を用いたEDLT構造によるキャリア蓄積が大きな成功を収めている。しかしながらこのEDLTの動作メカニズムについて、適用試料の性質に応じて純粋なキャリアドープ以外の様々な効果が報告され、議論が収束していない物質例も多い。本研究成果に基づき、困難なEDLT動作時のキャリア蓄積領域の軟X線吸収分光計測が実現可能となることで、EDLTの動作メカニズムの理解が劇的に進展することが期待でき、基礎物性研究・応用技術研究の双方に非常に大きな意義を有する。