Electronic structure of heavily electron-doped BaFe${}_{1.7}$Co${}_{0.3}$As${}_2$ studied by angle-resolved photoemission

Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy on heavily electron-doped non-superconducting (SC) BaFe${}_{1.7}$Co${}_{0.3}$As${}_2$. We find that the two hole Fermi surface pockets at the zone center observed in the hole-doped superconducting Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ are absent or very small in this compound, while the two electron pockets at the M point significantly expand due to electron doping by the Co substitution. Comparison of the Fermi surface between non-SC and SC samples indicates that the coexistence of hole and electron pockets connected via the antiferromagnetic wave vector is essential in realizing the mechanism of superconductivity in the iron-based superconductors.

5 pages, 4 figures