Spin-polarized surface states of topological Kondo insulator coupled with magnetic single atoms

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K21119
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 28:Nano/micro science and related fields
• Research Institution: Nagoya University (2021-2023); The University of Electro-Communications (2020)
• Principal Investigator: Miyamachi Tosiho 名古屋大学, 未来材料・システム研究所, 准教授 (10437361)
• Project Period (FY): 2020-07-30 – 2024-03-31
• Keywords: トポロジカル絶縁体 / 走査トンネル顕微鏡 / 近藤効果 / スピン

Outline of Final Research Achievements

We investigated topological surface states of Kondo insulator SmB6 in terms of surface structures and electronic correlation (Kondo effect) by scanning tunneling microscopy (STM). By controlling annealing temperature during sample preparation, we successfully prepared SmB6(001) surfaces with p(1×1), c(2×2) and (3×1) lattices. STM spectroscopic measurements revealed impacts of surface structures on the band gap and band dispersion of surface states both from real- and k-spaces. Furthermore, the role of the electronic correlation on the emergence of topological surface states was investigated from surface-structure dependence of the magnetic interaction between Co single atoms and SmB6(001) surfaces.

Free Research Field

表面科学、ナノ磁性

Academic Significance and Societal Importance of the Research Achievements

本研究でトポロジカル近藤絶縁体候補物質であるSmB6の金属表面状態をSTMによる原子分解能観察により詳細に調べ、表面構造や磁気相互作用により制御できる可能性が示された。得られた結果から、強相関電子系特有の新奇量子現象の発現の鍵を握るトポロジカル近藤絶縁体のトポロジカル物性の発現機構を理解することによって、超低消費電力で飛躍的に高い電子移動度を持つスピンデバイス創製につながることが期待できる。