  We have performed first-principles calculations using density functional
theory on a kagome lattice model with a chiral spin state, as a representative
example demonstrating significant longitudinal and transverse thermoelectric
properties. The results revealed that the saddle-point-type van Hove
singularity (VHS) enhances thermoelectric effects. The longitudinal
thermoelectric conductivity $\alpha_{xx}$ was large at the chemical potentials
tuned close to the band at the symmetry points, K (lower band edge), $\Gamma$
(upper band edge), and M (saddle point), where the VHSs of the density of
states (DOS) were at the corresponding band energies. The transverse
thermoelectric conductivity $\alpha_{xy}$ was large at the chemical potential
of saddle-point-type VHS. A large anomalous Nernst coefficient of about 10
$\mu$V/K at 50 K was expected.
