Effect of Pt substitution on the electronic structure of AuTe2

TL;DR

This study investigates how Pt substitution affects the electronic structure of AuTe2, revealing complex hybridization effects and challenging simple doping models, with implications for understanding superconductivity in this material.

Contribution

It provides detailed spectroscopic analysis showing the impact of Pt substitution on electronic states and hybridization in AuTe2, offering new insights into its superconducting behavior.

Findings

Au 4f and Te 3d spectra suggest Au2+ valence state

Au 5d bands are nearly fully occupied

Pt substitution does not follow a simple rigid band model

Abstract

We report a photoemission and x-ray absorption study on 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 suggests a valence state of Au2+(Te2)2-, which is consistent with its distorted crystal structure with Te-Te dimers and compressed AuTe6 otahedra. On the other hand, valence-band photoemission spectra and pre-edge peaks of 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. 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.