Electronic structure of the ultrafast nonequilibrium

2022 Fiscal Year Final Research Report

• Project/Area Number: 18H01148
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: The University of Tokyo
• Principal Investigator: Ishida Yukiaki 東京大学, 大学院理学系研究科(理学部), 特任講師 (30442924)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 時間分解光電子分光 / トポロジカル絶縁体 / 光起電力 / 非占有側バンド分散 / キャリアダイナミクス

Outline of Final Research Achievements

We conducted a precise electronic study of non-equilibrium phenomena occurring in solid materials and their surfaces using two time-resolved ARPES (Angle-Resolved Photoemission Spectroscopy) instruments. Specifically, we pursued the following themes:
1: Utilizing the principle that ARPES can directly observe the band dispersion of non-occupied states, we advanced the classification of topological phases in materials. 2: Taking advantage of the ability to observe optical phenomena on the scale of a few nanometers at the solid surface, we investigated novel functionalities based on optical photocurrents, inversion layer distributions, and excitation persistence approaching nanoseconds in topological insulator surfaces. This research contributes to the development of THz-range optical functionalization and optoelectronics.3: In pursuit of understanding non-equilibrium dynamics and establishing governing principles, we performed high-precision measurements of carrier dynamics.

Free Research Field

超高速電子ダイナミクス

Academic Significance and Societal Importance of the Research Achievements

本研究により固体物質における非平衡現象の理解が進み、トポロジカル相の分類が進展し、光エレクトロニクスのための新しい機能が探求され、キャリアダイナミクスの高精度測定が確立された。これらの知見は材料科学や凝縮物理学などの分野に影響を与え、先端技術の開発に寄与する可能性がある。