Thermoelectric properties of polycrystalline palladium sulfide.

A suite measurements of the electrical, thermal, and vibrational properties are conducted on palladium sulfide (PdS) in order to investigate its thermoelectric performance. The tetragonal structure with the space group $P$42/$m$ for PdS is determined from X-ray diffraction measurement. The unique temperature dependence of mobility suggests that acoustic phonons and ion impurity scattering are two dominant scattering mechanisms within the compound. The obtained power factor of $27$ $\mu$Wcm$^{-1}$K$^{-2}$ at 800 K is the largest value in the remaining transition-metal sulfides studied so far. The maximum value of the dimensionless figure of merit is 0.33 at 800 K. The observed phonon softening with temperature indicates that the reduction of the lattice thermal conductivity is mainly controlled by the enhanced lattice anharmonicity. These results indicate that the binary bulk PdS has promising potential to have good thermoelectrical performance.