Unusual Band Splitting and Superconducting Gap Evolution with Sulfur Substitution in FeSe  

作　　者：Yuanyuan Yang Qisi Wang Shaofeng Duan Hongliang Wo Chaozhi Huang Shichong Wang Lingxiao Gu Dong Qian Jun Zhao Wentao Zhang 杨媛媛;王奇思;段绍峰;沃弘樑;黄超之;王石崇;顾凌霄;钱冬;赵俊;张文涛(Key Laboratory of Artifcial Structures and Quantum Control(Ministry of Education),Shenyang National Laboratory for Materials Science,School of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China;State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China;Institute of Nanoelectronics and Quantum Computing,Fudan University,Shanghai 200433,China)

机构地区：[1]Key Laboratory of Artifcial Structures and Quantum Control(Ministry of Education),Shenyang National Laboratory for Materials Science,School of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China [2]State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China [3]Institute of Nanoelectronics and Quantum Computing,Fudan University,Shanghai 200433,China

出　　处：《Chinese Physics Letters》2022年第5期76-81,共6页中国物理快报（英文版）

基　　金：supports from the National Key R&D Program of China(Grant No.2021YFA1401800);the National Natural Science Foundation of China(Grant Nos.11974243 and 12141404);support from a Shanghai talent program;support from the National Natural Science Foundation of China(Grant No.12074248);Fudan University was supported by the Innovation Program of Shanghai Municipal Education Commission(Grant No.2017–01-07-00-07-E00018);the National Natural Science Foundation of China(Grant No.11874119)。

摘　　要：High-resolution angle-resolved photoemission measurements were taken on FeSe;S;(x=0,0.04,and 0.08)superconductors.With an ultrahigh energy resolution of 0.4 meV,unusual two hole bands near the Brillouin-zone center,which was possibly a result of additional symmetry breaking,were identified in all the sulfur-substituted samples.In addition,in both of the hole bands highly anisotropic superconducting gaps with resolution limited nodes were evidenced.We find that the larger superconducting gap on the outer hole band is reduced linearly to the nematic transition temperature while the gap on the inner hole is nearly S-substitution independent.Our observations strongly suggest that the superconducting gap increases with enhanced nematicity although the superconducting transition temperature is not only governed by the pairing strength,demonstrating strong constraints on theories in the FeSe family.

关 键 词：BANDS SULFUR substituted 

分 类 号：O469[理学—凝聚态物理]