The SiPb monolayer with high thermoelectric performance at room temperature

The SiPb monolayer with low lattice thermal conductivity and high dimensionless figure of merit (ZT) is identified by the first-principles calculations. The geometrical configuration is optimized, and the stabilities are confirmed with phonon dispersion and ab initio molecular dynamics simulation. The effective mass, mobility, and relaxation time are calculated by using the deformation theory. Based on the semiclassical Boltzmann transport theory and the band alignment by the Heyd-Scuseria-Ernzerhof hybrid functional, the Seebeck coefficient, electrical conductivity, power factor, and electron thermal conductivity relative to the carrier and temperature are obtained, while the ZT dependent on temperature is envaulted with the bipolar effect. The obtained ZT of 0.666/0.907 in the x/y-direction at 310 K supports the SiPb monolayer as a very promising application in implantable bioelectronics and wearable electronics.