Abstract
We utilize fine-tuned polarization selection coupled with excitation-energy variation of photoelectron signal to image the complete -band dispersion relation in sodium cobaltates. A hybridization gap anticrossing is observed along the Brillouin zone corner and the full quasiparticle band is found to emerge as a many-body entity lacking a pure orbital polarization. At low dopings, the quasiparticle bandwidth (Fermion scale, many-body ) is found to be smaller than most known oxide metals. The low-lying density of states is found to be in agreement with bulk-sensitive thermodynamic measurements for nonmagnetic dopings where the 2D Luttinger theorem is also observed to be satisfied.
- Received 28 June 2006
DOI:https://doi.org/10.1103/PhysRevLett.97.186405
©2006 American Physical Society