Solid State and Structural Chemistry Unit
Indian Institute of Science, Bangalore – 560 012
Professor A. Chainani
National Synchrotron Radiation Research Center
Evidence for Weakly Correlated Oxygen Holes in the Highest-Tc Cuprate Superconductor HgBa2Ca2Cu3O8 + δ
Date & Time : Friday 16th February, 2018 at 4:00 PM
Venue : SSCU Auditorium
We study the electronic structure of HgBa2Ca2Cu3O8þδ (Hg1223; Tc = 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 significantly different on-site Coulomb energies for the Cu site (Udd = 6.5 +/- 0.5 eV) compared to the Oxygen site (Upp = 1.0 +/- 0.5 eV). Cu2O7-cluster calculations with nonlocal screening explain the Cu 2p core level PES and Cu L-edge XAS spectra. The results confirm the Udd and Upp 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 .
 A. Chainani, M. Sicot, Y. Fagot-Revurat, G. Vasseur, J. Granet, B. Kierren, L. Moreau, M. Oura, A. Yamamoto, Y. Tokura, and D. Malterre, Physical Review Letters 19, 057001 (2017).
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