Unified origin for superconductivity, magnetism, and large thermopower in image Original Research Article

We argue that the large thermopower, magnetism, and superconductivity observed in NaxCoO2NaxCoO2 share the same origin, namely, the peculiar shape of the a1ga1g band. Superconductivity and magnetism arise from the local minimum structure of the band at the ΓΓ point, while the thermopower originates from the overall “pudding mold” shape of the band. Our study shows the importance of the band structure and the Fermi surface even in strongly correlated systems.