Effect of Pt substitution on the electronic structure of AuTe2

We report a photoemission and x-ray absorption study on a Au1-xPtxTe2 (x=0 and 0.35) triangular lattice in which superconductivity is induced by Pt substitution for Au. Au 4f and Te 3d core-level spectra of AuTe2 suggest a valence state of Au2+(Te2)2-, which is consistent with its distorted crystal structure with Te-Te dimers and compressed AuTe6 octahedra. On the other hand, valence-band photoemission spectra and preedge peaks of the Te 3d absorption edge indicate that Au 5d bands are almost fully occupied and that Te 5p holes govern the transport properties and the lattice distortion. The two apparently conflicting pictures can be reconciled by strong Au 5d/Au 6s-Te 5p hybridization. The absence of a core-level energy shift with Pt substitution is inconsistent with the simple rigid band picture for hole doping. The Au 4f core-level spectrum gets slightly narrow with Pt substitution, indicating that the small Au 5d charge modulation in distorted AuTe2 is partially suppressed.