Detailed study of the electronic structure of the layered Na 0.7CoO2, doped Mott insulator with triangular Co lattice is performed by angle-resolved photoemission spectroscopy (ARPES). At low temperature Fermi surface is a centered hole pocket of hexagonal character shape in agreement with LDA. A broad valence band satellite at higher energies showing resonant enhancement at the 2p, 3p → 3d excitations indicates large on-site Hubbard-U ∼ 5 eV. A momentum dependent quasiparticle band near Fermi level that is flat and vanished at energies already above 70 meV or 80 meV gives a value of the single particle hopping t < 10 meV. This band is defined only in the region of non - Fermi liquid transport with linear growth of resistivity up to 120 K.
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- Condensed Matter Physics
- Cobalt oxyhydrates
- Electron correlations
- Mott insulator
- Photoelectron spectroscopy