Fermi Surface and Quasiparticle Dynamics of Na0.7CoO2 Investigated by Angle-Resolved Photoemission Spectroscopy
Abstract
We present the first angle-resolved photoemission study of Na0.7CoO2, the host material of the superconducting NaxCoO2·nH2O series. Our results show a hole-type Fermi surface, a strongly renormalized quasiparticle band, a small Fermi velocity, and a large Hubbard U. The quasiparticle band crosses the Fermi level from M toward Γ suggesting a negative sign of effective single-particle hopping teff (about 10meV) which is on the order of magnetic exchange coupling J in this system. Quasiparticles are well defined only in the T-linear resistivity (non-Fermi-liquid) regime. Unusually small single-particle hopping and unconventional quasiparticle dynamics may have implications for understanding the phase of matter realized in this new class of a strongly interacting quantum system.
- Publication:
-
Physical Review Letters
- Pub Date:
- June 2004
- DOI:
- arXiv:
- arXiv:cond-mat/0308438
- Bibcode:
- 2004PhRvL..92x6402H
- Keywords:
-
- 71.20.-b;
- 73.20.At;
- 74.70.-b;
- 74.90.+n;
- Electron density of states and band structure of crystalline solids;
- Surface states band structure electron density of states;
- Superconducting materials;
- Other topics in superconductivity;
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- Revised text, Added Figs, Submitted to PRL