We analyze the origin of the three-dimensional (3D) magnetism observed in nonhydrated Na-rich NaxCoO2 within an itinerant spin picture using a 3D Hubbard model. The origin is identified as the 3D nesting between the inner and outer portions of the Fermi surface, which arise due to the local minimum structure of the a1g band at the Γ-A line. The calculated spin wave dispersion strikingly resembles the neutron scattering result. We argue that this 3D magnetism and the spin fluctuations responsible for superconductivity in the hydrated systems share essentially the same origin.
ASJC Scopus subject areas
- Physics and Astronomy(all)