Electronic Structure of the BaFe2As2 Family of Iron-Pnictide Superconductors.

摘要

We use high-resolution angle-resolved photoemission to study the electronic structure of the BaFe2As2 pnictides. We observe two electron bands and two hole bands near the X point, (7T,7T) of the Brillouin zone, in the paramagnetic state for electron-doped Ba(CoO.06Feo.94hAs2, undoped BaFe2As2, and hole-doped BaO.6K0.4Fe2As2). Among these bands, only the electron bands cross the Fermi level, forming two electron pockets around X while the hole bands approach but never reach the Fermi level. We show that the band structure of the BaFe2As2 family matches reasonably well with the prediction of local-density approximation calculations after a momentum-dependent shift and renormalization. Our finding resolves a number of inconsistencies regarding the electronic structure of pnictides.