Doping induced band renormalization in 122-type Fe-based superconductor

We study the electronic structure of a superconducting composition of 122-type Fe-based pnictide material, CaFe 1.9 Co 0.1 As 2 employing high resolution angle resolved photoemission spectroscopy technique. The experimental results exhibit three bands close to Fermi level at Γ-point of the Brillouin zone among which only one band crosses the Fermi level. In the parent compound, CaFe 2 As 2 , all the three bands cross the Fermi level and form three hole pockets. While the destruction of Fermi pockets due to electron doping (Co-substitution dopes electrons into the system) is expected, we observe significant orbital selective band renormalization with respect to the parent compound. It appears that the effect of spin-orbit coupling is stronger in the doped compound.