摘要
High resolution angle-resolved photoemission spectroscopy(ARPES)measurements are carried out on CaKFe_4 As_4,KCa_2 Fe_4 As_4 F_2 and(Ba_(0.6)K_(0.4))Fe_2 As_2 superconductors.Clear evidence of band folding between the Brillouin zone center and corners with a(π,π)wave vector has been found from the measured Fermi surface and band structures in all the three kinds of superconductors.A dominant √2×√2 surface reconstruction is observed on the cleaved surface of CaKFe_4As_4 by scanning tunneling microscopy(STM)measurements.We propose that the commonly observed √2×√2 reconstruction in the FeAs-based superconductors provides a general scenario to understand the origin of the(π,π)band folding.Our observations provide new insights in understanding the electronic structure and superconductivity mechanism in iron-based superconductors.
作者
蔡永青
谢涛
杨欢
吴定松
黄建伟
洪文山
曹路
刘畅
李聪
徐煜
高强
苗泰民
刘国东
李世亮
黄立
罗会仟
许祖彦
高鸿钧
赵林
周兴江
Yongqing Cai;Tao Xie;Huan Yang;Dingsong Wu;Jianwei Huang;Wenshan Hong;Lu Cao;Chang Liu;Cong Li;Yu Xu;Qiang Gao;Taimin Miao;Guodong Liu;Shiliang Li;Li Huang;Huiqian Luo;Zuyan Xu;Hongjun Gao;Lin Zhao;XJZhou(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;CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences,Beijing 100190,China;Beijing Academy of Quantum Information Sciences,Beijing 100193,China)
基金
Supported by the National Key Research and Development Program of China (Grant Nos.2016YFA0300300,2017YFA0302900,2018YFA0704200 and 2019YFA0308000)
the National Natural Science Foundation of China (Grant Nos.11888101,11922414 and11874405)
the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No.XDB25000000)
the Youth Innovation Promotion Association of CAS (Grant No.2017013)
the Research Program of Beijing Academy of Quantum Information Sciences (Grant No.Y18G06)。
