Realization of novel 2D topological insulator materials and its electronic structure analysis by spin-resolved ARPES

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01821
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 28030:Nanomaterials-related
• Research Institution: Tohoku University
• Principal Investigator: Sugawara Katsuaki 東北大学, 理学研究科, 准教授 (70547306)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: ２次元トポロジカル絶縁体 / 水素終端処理 / ARPES / MBE

Outline of Final Research Achievements

I have fabricated a 2DTI (two-dimensional topological insulator) like Bi monolayer film (called Bismuthene) by using a molecular-beam-epitaxy and characterized the electronic state like Dirac-electron and topological non-trivial edge state by angle-resolved photoemission spectroscopy (ARPES). Firstly, by developing a semiconductor hydrogen-annealing system, I obtained a clean hydrogen-terminated SiC (H-SIC) semiconductor surface. After depositing Bi atoms into H-SiC substrate, I clearly observed not only the superstructure patterns by LEED but also the hole-like dispersive feature by ARPES. These results indicate that we have succeeded in fabricating Bismuthene on H-SiC. In the future, I would clarify the band-gap feature of Dirac electrons and the edge-state in 2DTI. In this study. I also developed a new method for controlling the Dirac electrons by 2DTI heterostructures.

Free Research Field

光電子固体物性学

Academic Significance and Societal Importance of the Research Achievements

2DTIを実験的に実現させ近年注目を集めているスピントロニクス分野へ応用展開を行うためには、成長する半導体基板のダングリングボンドを異なる原子で終端させ清浄な基板を得ることと、金属的な性質を持たない基板上に成長させることが強く求められる。本研究では、上記について解決することで、新たな2DTIを生成することが可能であり、2DTI特有のエッジ物性開拓に一つの道を開くことが可能となり、大きな意義を持つと研究者は考えている。