Development of superconducting density functional theory for conventional and unconventional superconductors

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K14654
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: The University of Tokyo
• Principal Investigator: Nomoto Takuya 東京大学, 大学院工学系研究科(工学部), 助教 (60804200)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 超伝導 / 第一原理計算 / 超伝導密度汎関数理論 / Migdal-Eliashberg理論

Outline of Final Research Achievements

In this project, we have developed a non-empirical method to calculate superconductivity. In particular, we have introduced the spin-orbit interaction into the superconducting density functional theory and implemented the odd-parity paring to analyze the mechanism of superconductivity in Sn1-xInxTe and CuxBi2Se3. We have also succeeded in quantitatively evaluating the transition temperature of superconductors with low transition temperatures. This has been achieved using the ab initio Migdal-Eliashberg calculation combining with the intermediate representation basis and the sparse sampling method.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

超伝導密度汎関数理論へのスピン軌道相互作用の導入や奇パリティ超伝導計算の実装は、トポロジカル超伝導をはじめとする非従来型超伝導を第一原理的に計算する枠組みを提供する点で意義深い。また、本研究課題で、高精度な超伝導計算手法である第一原理Migdal-Eliashberg計算を転移温度の低い超伝導体に適用することが可能になった。これにより今まで超伝導密度汎関数理論では説明できなかった超伝導体の発現機構に、別手法からアプローチすることが可能となった。