  We studied the low-lying electronic structure of the newly discovered
iron-platinum-arsenide superconductor, Ca10(Pt4As8)(Fe2-xPtxAs2)5 (Tc=22 K)
with angle-resolved photoemission spectroscopy. We found that the Pt4As8 layer
contributes to a small electron-like Fermi surface, indicative of metallic
charge reservoir layers that are rare for iron based superconductors. Moreover,
the electronic structure of the FeAs-layers resembles those of other prototype
iron pnictides to a large extent. However, there is only dxy-orbital originated
hole-like Fermi surface near the zone center, which is rather unique for an
iron pnictide superconductor with relatively high superconducting transition
temperature; and the dxz and dyz originated bands are not degenerate at the
zone center. Furthermore, all bands near the Fermi energy show negligible kz
dependence, indicating the strong two-dimensional nature of this material. Our
results indicate this material possesses rather unique electronic structure,
which enriches our current knowledge of iron based superconductors.
