近日，中国科学院物理研究所的周兴江&赵林及其研究团队取得一项新进展。经过不懈努力，他们揭示单空穴口袋铁基超导体中的节点s±配对对称性。相关研究成果已于2024年1月23日在国际知名学术期刊《自然—物理学》上发表。
该研究团队确定了KFe2As2的配对对称性也是s±型的。KFe2As2是一种典型的铁基超导体，在区中心和区角周围都有电子口袋。研究人员基于激光的角分辨光发射测量确定了超导能隙分布，并确定了区中心和区角周围所有费米表面上能隙节点的位置。这些结果统一了空穴掺杂铁基超导体的配对对称性，并指出自旋涨落是产生超导的配对胶。
据悉，尽管铁基超导体的高温超导性起源仍未明确，但确定配对对称性对于理解超导机制至关重要。在铁基超导体中，布里渊区中心周围的电子口袋和区角周围的电子口袋的配对对称性通常被认为是s±，这表明空穴和电子口袋之间的超导能隙发生了符号变化。然而，对于只有电子口袋的铁基超导体，尽管已经提出了多个配对方案，但确切的对称性仍然存在争议。
附：英文原文
Title: Nodal s± pairing symmetry in an iron-based superconductor with only hole pockets
Author: Wu, Dingsong, Jia, Junjie, Yang, Jiangang, Hong, Wenshan, Shu, Yingjie, Miao, Taimin, Yan, Hongtao, Rong, Hongtao, Ai, Ping, Zhang, Xing, Yin, Chaohui, Liu, Jieyi, Chen, Houke, Yang, Yiheng, Peng, Cheng, Li, Chenlong, Zhang, Shenjin, Zhang, Fengfeng, Yang, Feng, Wang, Zhimin, Zong, Nan, Liu, Lijuan, Li, Rukang, Wang, Xiaoyang, Peng, Qinjun, Mao, Hanqing, Liu, Guodong, Li, Shiliang, Chen, Yulin, Luo, Huiqian, Wu, Xianxin, Xu, Zuyan, Zhao, Lin, Zhou, X. J.
Issue&Volume: 2024-01-23
Abstract: The origin of high-temperature superconductivity in iron-based superconductors is still not understood; determination of the pairing symmetry is essential for understanding the superconductivity mechanism. In the iron-based superconductors that have hole pockets around the Brillouin zone centre and electron pockets around the zone corners, the pairing symmetry is generally considered to be s±, which indicates a sign change in the superconducting gap between the hole and electron pockets. For the iron-based superconductors with only hole pockets, however, a couple of pairing scenarios have been proposed, but the exact symmetry is still controversial. Here we determine that the pairing symmetry in KFe2As2—which is a prototypical iron-based superconductor with hole pockets both around the zone centre and around the zone corners—is also of the s± type. Our laser-based angle-resolved photoemission measurements have determined the superconducting gap distribution and identified the locations of the gap nodes on all the Fermi surfaces around the zone centres and the zone corners. These results unify the pairing symmetry in hole-doped iron-based superconductors and point to spin fluctuation as the pairing glue in generating superconductivity.
DOI: 10.1038/s41567-023-02348-1
Source: https://www.nature.com/articles/s41567-023-02348-1