Thermoelectric power of single-orbital and two-orbital Hubbard models on triangular lattices

The thermoelectric power of the single-orbital and two-orbital correlated electron systems on a two-dimensional triangular lattice is investigated by the dynamical mean field theory with the exact diagonalization solver at finite temperature. It reveals that for the hole doping case, the geometrical frustration together with the Coulomb interaction greatly enhances thermoelectric power, in comparison with the electron doping case. In an anisotropic triangular lattice, we find a large thermoelectric power in the direction with small hopping integral in the anisotropic systems. In the two-orbital systems, we show that though the orbital entropy contributes to thermoelectric power, Hund's rule coupling may suppress the large thermoelectric power.