The orbital characters of low-energy electronic structure in iron-chalcogenide superconductor KxFe2-ySe2

Abstract

The newly discovered iron-chalcogenide superconductor KxFe2-ySe2 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 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 between them. Moreover, in contrast to the band calculation results, the small electron pocket around Z is found to be mainly consisted of the dZ orbital. The determined orbital characters would help to construct a realistic model for KxFe2-ySe2. © 2012 The Author(s).