Computational prediction of high thermoelectric performance in p-type CuGaTe2 with a first-principles study

The excellent p-type thermoelectric (TE) performance of ternary chalcopyrite I-III-IV2 originates from its distinctive crystal structure and superior electrical transport properties. Here, we applied the first-principles method and Boltzmann theory to calculate the electronic band structure and electrical transport performance of CuGaTe2. We also calculated the phonon spectrum and thermal conductivity of this material. The calculated lattice thermal conductivity of CuGaTe2 was higher than that of other TE materials given its large Debye temperature and low Gruneisen parameter. These characteristics proved that enhancing phonon scattering can effectively improve the TE performance of CuGaTe2. The predicted maximum zT value of p-type CuGaTe2 was 3.8 over the optimal carrier concentration range at 900 K and minimum lattice thermal conductivity. This value was considerably larger than previously reported experimental values. Given its high predicted zT, p-type CuGaTe2 is a promising TE material with potential applications in midtemperature power generation.