Detection and control of Majorana particle in vortex core of topological superconductors

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H01843
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Machida Tadashi 国立研究開発法人理化学研究所, 創発物性科学研究センター, 上級研究員 (60570695)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: トポロジカル超伝導体 / マヨラナ粒子 / 超伝導渦糸 / 走査型トンネル顕微鏡

Outline of Final Research Achievements

The aim of this project is to establish the ways to detect and control the Majorana quasiparticles in the vortex core of a topological superconductor, using scanning tunneling microscope (STM). We succeeded in observing zero-energy excitations consistent with the Majorana zero mode in the vortex core of the topological superconductor FeSeTe, and also found that these zero-energy excitations disappear with increasing external magnetic field. This magnetic field dependence suggests the possibility of controlling the Majorana quasiparticles by an external magnetic field. In addition, we have established the way to make a Yu-Shiba-Rusinov STM tip with extremely high spin resolution, which provides an unambiguous way to detect the spin polarization of the Majorana zero mode.

Free Research Field

超伝導

Academic Significance and Societal Importance of the Research Achievements

トポロジカル超伝導体におけるマヨラナ準粒子は，その特異な性質を利用した新たな量子計算技術(トポロジカル量子計算)の基本構成要素として大きな注目を集めている.本研究では,マヨラナ準粒子の重要な特徴であるゼロエネルギー励起の検出に成功し,さらにその外部磁場応答を微視的立場から明らかにした．これらの結果は今後の量子計算技術への応用において極めで重要な知見を与える．さらに新たに開発したYu-Shiba-Rusinov状態を用いたスピン偏極分光技術も今後のマヨラナ準粒子の研究においてその検出法の一翼を担うと期待される．