Magnetic field dependence of thermopower in strongly correlated electron systems

強相関電子系における熱起電力の磁場効果

松尾 まり; 岡本 敏史*; 小椎八重 航*; 森 道康  ; 前川 禎通

Matsuo, Mari; Okamoto, Satoshi*; Koshibae, Wataru*; Mori, Michiyasu; Maekawa, Sadamichi

The cobalt oxides, NaCoO have a large thermopower due to an entropy transport by the degrees of freedom of electron's spin and orbital as characteristics of strongly correlated electron systems. Wang et al. observed much larger magnetic field response of thermopower of NaCoO at low temperatures than usual metals. Motivated by their observation of the huge magnetic field response of thermopower, we investigate theoretically effects of strong correlation between electrons on the field response of thermopower at low temperatures. We study magnetic field dependence of the Seebeck coefficient of the single band Hubbard model using Dynamical Mean Field Theory and non-crossing approximation as one-site Anderson impurity solver. Our results show that the strong Coulomb interaction derives a narrow quasi-particle band structure and a large response of the Seebeck coefficient to magnetic field.