DOI: 10.1016/j.scib.2021.05.015
论文题名: Genuine electronic structure and superconducting gap structure in (Ba0.6K0.4)Fe2As2 superconductor
作者: Cai Y. ; Huang J. ; Miao T. ; Wu D. ; Gao Q. ; Li C. ; Xu Y. ; Jia J. ; Wang Q. ; Huang Y. ; Liu G. ; Zhang F. ; Zhang S. ; Yang F. ; Wang Z. ; Peng Q. ; Xu Z. ; Zhao L. ; Zhou X.J.
刊名: Science Bulletin
ISSN: 20959273
出版年: 2021
语种: 英语
中文关键词: (Ba0.6K0.4)Fe2As2
; ARPES
; Band folding
; Electronic structure
; Superconducting gap
英文摘要: The electronic structure and superconducting gap structure are prerequisites to establish microscopic theories in understanding the superconductivity mechanism of iron-based superconductors. However, even for the most extensively studied optimally-doped (Ba0.6K0.4)Fe2As2, there remain outstanding controversies on its electronic structure and superconducting gap structure. Here we resolve these issues by carrying out high-resolution angle-resolved photoemission spectroscopy (ARPES) measurements on the optimally-doped (Ba0.6K0.4)Fe2As2 superconductor using both Helium lamp and laser light sources. Our results indicate the “flat band” feature observed around the Brillouin zone center in the superconducting state originates from the combined effect of the superconductivity-induced band back-bending and the folding of a band from the zone corner to the center. We found direct evidence of the band folding between the zone corner and the center in both the normal and superconducting state. Our resolution of the origin of the flat band makes it possible to assign the three hole-like bands around the zone center and determine their superconducting gap correctly. Around the zone corner, we observe a tiny electron-like band and an M-shaped band simultaneously in both the normal and superconducting states. The obtained gap size for the bands around the zone corner (~5.5 meV) is significantly smaller than all the previous ARPES measurements. Our results establish a new superconducting gap structure around the zone corner and resolve a number of prominent controversies concerning the electronic structure and superconducting gap structure in the optimally-doped (Ba0.6K0.4)Fe2As2. They provide new insights in examining and establishing theories in understanding superconductivity mechanism in iron-based superconductors. © 2021 Science China Press Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170197
Appears in Collections: 气候变化与战略
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作者单位: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Songshan Lake Materials Laboratory, Dongguan, 523808, China; Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China; Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
Recommended Citation:
Cai Y.,Huang J.,Miao T.,et al. Genuine electronic structure and superconducting gap structure in (Ba0.6K0.4)Fe2As2 superconductor[J]. Science Bulletin,2021-01-01