Theoretical studies to establish experimental methods of determination of gap structures in unconventional superconductors

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K05553
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Ritsumeikan University
• Principal Investigator: Machida Kazushige 立命館大学, 総合科学技術研究機構, プロジェクト研究員 (50025491)
• Project Period (FY): 2017-04-01 – 2023-03-31
• Keywords: 非自明超伝導体 / 超伝導ギャップ構造 / 重い電子系 / 強相関電子系

Outline of Final Research Achievements

One of the main purposes of this study is to determine the gap structure in non-trivial superconductors, which exhibit unconventional physical properties unseen in conventional superconductors. This study is important in uncovering the pairing mechanism in such materials, which may ultimately lead to novel superconductor with high transition temperature. In this study we take up several unconventional superconductors in order to determine their gap structures. In some of them the gap structures are unambiguously determined by using field rotation specific heat measurement, but there remain undetermined due to sample quality. Namely the heavy Fermion superconductor UTe2, which is one of the focus in condensed matter community and claimed to be a point node gap structure by us must be rechecked by using ultra-high quality samples with Tc=2K. This is an urgent next work.

Free Research Field

物性理論

Academic Significance and Societal Importance of the Research Achievements

当該研究は物性物理学の根底にある自然界が示す自然法則を具体的、個別的な物質に着目して解き明かそうとする試みである。そうした文脈の中で当該研究の達成した成果は確実な基礎の一つを物性分野に加えたと言える。即ち、超伝導ギャップ決定の強力な手段の提供は今後この分野の発展の基盤的な知見を与えたと言える。こうした知見はより広い立場、即ち社会的な観点から見ても直接的な応用は無いにしろ汎用性を有しており、将来にわたって有効なものであり十分に社会的な意義を持っていると言える。