DFT Insights on the Electronic and Thermoelectric Properties of CuGaTe2 under Pressure

The band structures of CuGaTe2 are very sensitive to the variation of lattice parameters because of the strong interaction between the Cu-d and Te-p valence electrons near Fermi level. In our study, the band convergence appeared for CuGaTe2 under the pressure of 3.8 GPa. These converged bands would be propitious to improve the thermoelectric properties of n-type CuGaTe2. Two factors lead to rapid band convergence. One is the energy level increased more rapidly at Gamma point than the X point near conduction band minimum along with the increased pressure. The other factor is the rapidly decreased value of valence band maximum at X point relative to the value at Gamma point. The thermoelectric performance could be improved because of the band convergence for n-type CuGaTe2.