High-temperature superconductivity in surface/interface systems by first-principles calculations

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K03716
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Mie University
• Principal Investigator: Sano Kazuhiro 三重大学, 工学研究科, 教授 (40201537)
• Co-Investigator(Kenkyū-buntansha): 大野 義章 新潟大学, 自然科学系, 教授 (40221832) ; 中村 浩次 三重大学, 工学研究科, 教授 (70281847)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 超伝導 / 第一原理計算

Outline of Final Research Achievements

The purpose of this study is to elucidate the mechanism of high-temperature superconductivity reported in tungsten bronze surface systems and interface systems in iron-based superconductors. These systems have a superconducting transition temperature Tc of around 100K even under normal pressure, which is very interesting because it is close to the transition temperature observed in the well-known copper oxide system. These systems show superconductivity even in the bulk state, but their Tc is less than 10K, and it is highly possible that the Tc is greatly increased by the surface and interface effects. Therefore, we hypothesized that the essence of these superconducting mechanisms might be expressed by the mutual cooperation of phonons and electron correlations, and examined them by first-principles calculations. These results have been compiled and published as a paper.

Free Research Field

物性理論

Academic Significance and Societal Importance of the Research Achievements

巨視的な量子現象である超伝導は学術的に興味深いだけでなく、高い超伝導転移温度を持つ物質が発見されれば、それを用いた電子デバイスや強力な電磁石への応用等が期待され大きな社会的意義を持つ。本研究では第一原理計算を用いて超伝導機構として従来から知られていたフォノンに加え電子相関の効果を加えたメカニズムが、新しい高温超伝導メカニズムの候補になりえるかどうかを検討した。常圧下ではフォノンメカニズムだけでは高い転移温度を実現することは難しいものと考えられるが、これに電子相関の効果を加えれば相乗的に高い転移温度が期待される訳である。本研究はこの新しい高温超伝導メカニズム研究の礎となったと考えられる。