The orbital characters of low-energy electronic structure in iron-chalcogenide superconductor K_xFe_(2-y)Se_2  

作　　者：CHEN Fei GE QingQin XU Min ZHANG Yan SHEN XiaoPing LI Wei MATSUNAMI Masaharu KIMURA Shin-ichi HU JiangPing FENG DongLai 

机构地区：[1]State Key Laboratory of Surface Physics,Department of Physics,and Advanced Materials Laboratory,Fudan University,Shanghai 200433,China [2]Department of Physics,Fudan University,Shanghai 200433,China [3]UVSOR Facility,Institute for Molecular Science and The Graduate University for Advanced Studies,Okazaki 444-8585,Japan [4]Department of Physics,Purdue University,West Lafayette,Indiana 47907,USA [5]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100080,China

出　　处：《Chinese Science Bulletin》2012年第30期3829-3835,共7页

基　　金：supported in part by the National Natural Science Foundation of China,Ministry of Education of China;the National Basic Research Program of China (2012CB921400,2011CB921802 and 2011CBA00112)

摘　　要：The newly discovered iron-chalcogenide superconductorKxFe2ySe2exhibits 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 aKxFe2ySe2superconductor.To a large extent,we find thatKxFe2ySe2superconductor 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 2 orbital.The determined orbital characters would help to construct a realistic model forKxFe2ySe2.The newly discovered iron-chalcogenide superconductor KxFe2_ySe2 exhibits a distinct electronic structure from other iron-based su- perconductors. Exploiting polarization-dependent angle-resolved photoemission spectroscopy, we have determined the orbital char- acters of band structure in a KxFe2_ySe2 superconductor. To a large extent, we find that KxFe2_ySe2 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 be- tween them. Moreover, in contrast to the band calculation results, the small electron pocket around Z is found to be mainly consisted of the dz2 orbital. The determined orbital characters would help to construct a realistic model for KxFe2_ySe2.

关 键 词：电子结构 轨道特征 铁基 低能量 角分辨光电子能谱 硫 超导体 几何形状 

分 类 号：O611.3[理学—无机化学]