The strain-induced excellent thermoelectric performance of PbTe

Through Density functional theory and Boltzmann transport theory, the ideal strength, electronic structure, elastic constants and thermoelectric performance of cubic phase PbTe are investigated. When the compressive strain is applied, both band gap and Seebeck coefficient decrease, while the electrical conductivity, power factor, thermal conductivity and ZT increase. According to the ZT of PbTe, the thermoelectric performance of p type is superior to that of n type. The optimal ZT value of p type could reach 3.88 at 0.5% strain, while the optimal ZT value of n type could reach 3.05 at 2.0% strain. Compared to the thermoelectric performance without strain, the thermoelectric performance under strain could be significantly improved, indicating that the strain engineering could be an effective strategy to improve the thermoelectric performance of PbTe.