Thermoelectric Transport Coefficients for Massless Dirac Electrons in Quantum Limit

We perform an analytic calculation of thermoelectric transport coefficients for massless Dirac electrons using the approach based on the Kubo--St\v{r}eda formula and generalized Mott's relation. The main focus of the letter is made on the properties of the Nernst coefficient in the vicinity of the Dirac point in quantum limit. We calculate magnetic field and temperature dependencies of the Nernst coefficient and compare our results with recent experiments in $\alpha$-(BEDT-TTF)$_{2}$I$_{3}$ organic conductor. We argue that the Zeeman splitting is important to understand the experimental data at high magnetic fields.