Anisotropic thermoelectric properties of Sr₅Sn₂As₆ compound under pressure by PBE-GGA and mBJ approaches

We have investigated the effect of pressure on the structural, electronic and thermoelectric properties of Sr 5 Sn 2 As 6 zintl compound using the full potential linearized augmented plane wave method and the Perdew– Burke– Ernzerhof-generalized gradient approximation and modified Becke–Johnson exchange correlation potentials. The anisotropic crystal structure is observed in the z -direction. The results show that the lattice parameters decrease and the size of the band gap increases with increasing pressure. The thermoelectric efficiency along the z -direction is better than the x -and y -directions with a maximum ZT value of 0.993 in 7.1 GPa. P-type doping of Sr 5 Sn 2 As 6 has better ZT than n-type doping.