A comparative study of thermoelectric properties of CuGaTe_2 by using PBE and MBJ potentials

摘要

We have investigated the electronic and thermoelectric properties of CuGaTe_2 by combining the first principle calculations with Boltzmann transport theory. The electronic properties show that CuGaTe_2 is a direct band semiconductor with large band gap at r-point. The band gaps are computed by using PBE and mBJ potentials and value obtained with mBJ is much closer to the experimental value. Partial density of states plots show that the band gap is formed by the hybridization between 3d states of Cu atom, 4s and 4p states of Ga atom and 5p states of Te atom. Very large value (～300μVK~(-1)) of Seebeck coefficient is obtained for this compound. Figure-of-merit calculated by using transport coefficients is also found to be very large for the entire temperature range and CuGaTe_2 is a good thermoelectric material.