Evidence for weakly correlated oxygen holes in the highest-T${}_c$ cuprate superconductor HgBa${}_2$Ca${}_2$Cu${}_3$O${}_{8+\delta }$

Abstract

We study the electronic structure of HgBa${}_2$Ca${}_2$Cu${}_3$O${}_{8+\delta }$ (Hg1223 ; T${}_c$ = 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 identify 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${}_{dd}$ = 6.5$\pm$0.5 eV) and O-site (U${}_{pp}$ = 1.0$\pm$0.5 eV). Cu${}_2$O${}_7$-cluster calculations with non-local screening explain the Cu 2p core level PES and Cu L-edge XAS spectra, confirm the U${}_{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.

11 pages, including supplementary material, added references