[1]National Center for Atmospheric Research, Research Applications Laboratory,Boulder,United States
[2]Fudan University, Collaborative Innovation Center of Advanced Microstructures,Shanghai,China
[3]Shanghai Jiao Tong University School of Medicine, Department of Endocrine and Metabolic Diseases,Shanghai,China
[4]Third Military Medical University, Department of Biochemistry and Molecular Biology,Chongqing,China
[5]Fudan University, Department of Physics,Shanghai,China
[6]Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics,Shanghai,China
[7]National Institutes of Natural Sciences - Institute for Molecular Science, UVSOR Facility,Okazaki,Japan
[8]Institute of Physics Chinese Academy of Sciences,Beijing,China
[9]Fudan University, Department of Chemistry and Laboratory of Advanced Materials,Shanghai,China
The newly discovered iron-chalcogenide superconductor K xFe 2-ySe 2 exhibits a distinct electronic structure from other iron-based superconductors. Exploiting polarization-dependent angle-resolved photoemission spectroscopy, we have determined the orbital characters of band structure in a K xFe 2-ySe 2 superconductor. To a large extent, we find that K xFe 2-ySe 2 superconductor shares similar orbital characters with other iron-based superconductors, but with its own characteristics. For example, we have resolved two highly degenerate electron cylinders around the zone corner in the s and p geometries, respectively, indicating negligible interactions between them. Moreover, in contrast to the band calculation results, the small electron pocket around Z is found to be mainly consisted of the d Z orbital. The determined orbital characters would help to construct a realistic model for K xFe 2-ySe 2. © 2012 The Author(s).
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