Evidence for Weakly Correlated Oxygen Holes in the Highest-Tc Cuprate Superconductor HgBa2Ca2Cu3O8+δ
Résumé
We study the electronic structure of HgBa 2 Ca 2 Cu 3 O 8þδ (Hg1223; T c ¼ 134 K) using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). Resonant valence band PES across the O K edge and Cu L edge identifies correlation satellites originating in O 2p and Cu 3d two-hole final states, respectively. Analyses using the experimental O 2p and Cu 3d partial density of states show quantitatively different on-site Coulomb energy for the Cu site (U dd ¼ 6.5 AE 0.5 eV) and O site (U pp ¼ 1.0 AE 0.5 eV). Cu 2 O 7-cluster calculations with nonlocal screening explain the Cu 2p core level PES and Cu Ledge XAS spectra, confirm the U dd and U pp values, and provide evidence for the Zhang-Rice singlet state in Hg1223. In contrast to other hole-doped cuprates and 3d-transition metal oxides, the present results indicate weakly correlated oxygen holes in Hg1223.
Domaines
Matière Condensée [cond-mat]
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