STM/STS and ARPES studies on impurity effects on high-temperature superconductivity and pseudogap in cuprates

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05155
• 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: Hokkaido University
• Principal Investigator: Oda Migaku 北海道大学, 理学研究院, 教授 (70204211)
• Co-Investigator(Kenkyū-buntansha): 黒澤 徹 北海道大学, 理学研究院, 助教 (10615420) ; 吉田 紘行 北海道大学, 理学研究院, 助教 (30566758)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 高温超伝導 / pseudogap / 超伝導ギャップ / 反強磁性結合 / 電子系超格子 / 不純物効果

Outline of Final Research Achievements

For the understanding of the relation of the antiferromagnetic coupling between Cu spins with the high-temperature superconducting mechanism and the origin of pseudogap phenomenon in cuprates, we performed STM/STS experiments at T<<Tc in pure and Ni-impurity doped Bi-based high-Tc cuprates, and also tried to make ARPES experiments. In high-Tc cuprates, it is well-known that the suppression effect on the superconductivity due to impurities is much weaker for magnetic Ni than for nonmagnetic Zn. The present study has demonstrated that such anomalous impurity effect on the high-Tc superconductivity can be explained in terms of the impurity effect on the antiferromagnetic coupling of Cu-spins. Furthermore, we have also obtained some results suggesting that the antiferromagnetic coupling is responsible for the pairing mechanism in high-Tc cuprates.

Free Research Field

固体電子物性