Electronic Phase Separation and Dramatic Inverse Band Renormalization in the Mixed-Valence Cuprate LiCu2 O2

S. Moser, Y. Nomura, L. Moreschini, G. Gatti, H. Berger, P. Bugnon, A. Magrez, C. Jozwiak, A. Bostwick, E. Rotenberg, S. Biermann, M. Grioni

Research output: Contribution to journalArticlepeer-review

Abstract

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu2O2, a mixed-valence cuprate where planes of Cu(I) (3d10) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d9) chains. We find that the Cu(I)- and Cu(II)-derived electronic states form separate electronic subsystems, in spite of being coupled by bridging O ions. The valence band, of the Cu(I) character, disperses within the charge-transfer gap of the strongly correlated Cu(II) states, displaying an unprecedented 250% broadening of the bandwidth with respect to the predictions of density functional theory. Our observation is at odds with the widely accepted tenet of many-body theory that correlation effects generally yield narrower bands and larger electron masses and suggests that present-day electronic structure techniques provide an intrinsically inappropriate description of ligand-to-d hybridizations in late transition metal oxides.

Original languageEnglish
Article number176404
JournalPhysical review letters
Volume118
Issue number17
DOIs
Publication statusPublished - 2017 Apr 28
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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