Thermoelectric power of Dirac fermions in graphene

On the basis of self-consistent Born approximation for Dirac fermions under charged impurity scatterings in graphene, we study the thermoelectric power using the heat current-current correlation function. The advantage of the present approach is its ability to effectively treat the low-doping case where the coherence process involving carriers in both upper and lower bands becomes important. We show that the low-temperature behavior of the thermoelectric power as a function of the carrier concentration and the temperature observed by the experiments can be successfully explained by our calculation.