Spectroscopic investigation for optical generation/control of surface spincurrent

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01875
• 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: National Institute for Materials Science
• Principal Investigator: ARAFUNE Ryuichi 国立研究開発法人物質・材料研究機構, 国際ナノアーキテクトニクス研究拠点, 主任研究員 (50360483)
• Co-Investigator(Kenkyū-buntansha): 高木 紀明 京都大学, 人間・環境学研究科, 教授 (50252416) ; 石田 浩 日本大学, 文理学部, 教授 (60184537)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 表面分光 / レーザー / スピン軌道相互作用 / 非占有状態

Outline of Final Research Achievements

The electronic structure of occupied and unoccupied states on solid surfaces were investigated by using laser photoelectron spectroscopy to study the nature of the photo-excited spin current and the effect of spin-orbit coupling. Graphene/Ir(111) was the main target of the measurements, and the image charge band, which is a typical example of the surface unoccupied state, was measured in detail.

On the theoretical side, we further developed the embedded Green function method. It is now possible to take into account spin-orbit interactions. Moreover we have been enable to calculate the electronic band structure of semi-infinite solid crystal surfaces even for relatively large unit cells including moire systems.

Free Research Field

表面科学

Academic Significance and Societal Importance of the Research Achievements

（光励起）スピン流研究の多くは、（正/逆）スピンホール効果に由来した伝導測定を用いた研究である。本研究はそれらの研究に対して分光学的側面から解明を目指したものであり、補完的な情報を提供できる。光励起状態はフェムト・ピコ秒オーダーの本質的に超高速現象であり、短パルスレーザーを用いる本手法は光励起スピン流の本質に直接アプローチ可能なものである。