High temperature atomic layer superconductivity realized with hydrogenation

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K18732
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Akiyama Ryota 東京大学, 大学院理学系研究科(理学部), 助教 (40633962)
• Project Period (FY): 2018-06-29 – 2023-03-31
• Keywords: 超伝導 / 原子層物質 / 層状物質 / ファンデルワールス物質 / 水素

Outline of Final Research Achievements

This research project is an attempt to increase the transition temperature of two-dimensional superconductivity in thin films such as FeSe and at surfaces and interfaces by modifying them with hydrogen. Although we have completed the fabrication and evaluation of FeSe thin films and performed superconductivity measurements, no clear transition of superconductivity could be seen. Although it took some time to elucidate these issues, we have not yet reached the point where we can stably perform hydrogen modification on the fabricated superconductors and measure systematic data, we will continue our research to explore the conditions for fabricating samples with high normal resistance, to clarify what makes them different from those with low resistance, and to determine the superconductivity transition temperature from the temperature dependence of the electrical resistance. We would like to confirm how it is changed by hydrogen modification as soon as possible.

Free Research Field

低次元ナノ量子物理学

Academic Significance and Societal Importance of the Research Achievements

FeSe薄膜の超伝導については未解明な点が多く、超伝導転移温度もばらついており、何がその要因となっているのか不明な点も多い。また作製法によって性質が大きく変わることが今回の研究結果から判明した。我々の試料は構造評価上はFeSeの単結晶で先行研究と同一にも関わらず、常伝導抵抗が先行研究に比べて顕著に低い。これをもたらす要因がボースメタルのような以上金属状態と結びつけて議論可能なのかなど、多くの疑問を投げかける結果となった。今後、より原子・電子構造も詳細に調べ、電気伝導の性質と絡めて解明していくことが必要で、その切り口を見つけたことが本研究の意義と言えるだろう。