Comparative ARPES Study on Iron–Platinum–Arsenide Superconductor Ca10(Pt4As8)(Fe2−xPtxAs2)5 (x = 0.25 and 0.42)

We studied the electronic structure of Ca10(Pt4As8)(Fe2−xPtxAs2)5 for two platinum concentrations with different Tc using ARPES. From the carrier number estimated from the areas of FS sheets, we found that the Pt substitution induces electron doping into the Fe2As2 layers (effectively two electrons per Pt atom). In addition, we found that the FS nesting condition in x = 0.25 is stronger than that in x = 0.42, indicating close correlation between the FS nesting and Tc.