Electronic states of bismuth layered materials with black-phosphorus-like structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K05493
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Nakatsuji Kan 東京工業大学, 物質理工学院, 准教授 (80311629)
• Co-Investigator(Kenkyū-buntansha): 平山 博之 東京工業大学, 理学院, 教授 (60271582)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 表面電子状態 / ビスマス超薄膜 / 光電子分光 / 走査トンネル顕微鏡

Outline of Final Research Achievements

Bi(110) ultra-thin films with black-phosphorous-like (BP-like) structure attract much interest as a candidate of two-dimensional topological insulator. In the present study, the atomic and electronic structures of Bi(110) ultra-thin films grown on silicon substrates are systematically investigated by angle-resolved photoelectron spectroscopy and scanning tunneling microscopy. It was reveled that the internal atomic structure of the film below 8 atomic layers is BP-like. The films are hole-doped by charge transfer from the substrate. The two-step growth in which the Bi atoms are deposited at 100 K followed by annealing to room temperature resulted in the films with unique height in a wide area.

Free Research Field

表面界面物性

Academic Significance and Societal Importance of the Research Achievements

黒リン構造のBi(110)超薄膜は、基板との相互作用や電荷移動によるトポロジカル絶縁体転移が予想されており、その電子状態が大変興味深いにもかかわらず、研究例は少ない状態であった。本研究により、デバイス整合性のよい半導体基板を用いて将来的に半導体技術で電荷量を制御する可能性を担保したうえで、Bi(110超薄膜の成長過程と電子状態についての系統的な知見を得ることができたことは、学術的にも社会的にも大変意義深いことと考えている。