Direct observation of strong correlations near the band insulator regime of Bi misfit cobaltates

V. Brouet*, A. Nicolaou, M. Zacchigna, A. Tejeda, L. Patthey, S. Hébert, Wataru Kobayashi, H. Muguerra, D. Grebille

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

We establish with angle-resolved photoemission spectroscopy (ARPES) that the electronic structure near the Fermi level of the "misfit" cobaltate [Bi2 Ba2 O4]·[Co O2] ∼2 is similar to that of Na cobaltates Nax Co O2. Both families of compounds contain triangular Co planes but in a different three-dimensional environment. We propose that the peculiar ARPES line shape of all cobaltates is of the "peak-dip-hump" type, due to strong many-body effects. We detect a progressive transfer of spectral weight from the quasiparticle feature near EF to a broad hump in misfit phases where Ba is replaced by Sr or Ca. This indicates stronger many-body interactions in proximity to the band insulator regime, which we attribute to the presence of unusual magnetic excitations.

Original languageEnglish
Article number100403
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume76
Issue number10
DOIs
Publication statusPublished - 2007 Sep 10
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics

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