Comment on " Low-Lying Quasiparticle States and Hidden Collective Charge Instabilities in Parent Cobaltate Superconductors"

I. I. Mazin, M. D. Johannes, G. A. Sawatzky

Qian et al [1] recently reported angular-resolved photoemission spectroscopy (ARPES) measurements for Na0.8CoO2 that show two concentric Fermi surfaces (FS) split by a delta k_F th…