Electronic and thermoelectric properties of natural layered structural compounds SrCuChF (Ch=S, Se and Te)

In this paper, we study the crystal structures, density of states, electronic band structures and thermoelectric transport properties of SrCuChF (Ch = S, Se and Te) by the way of the first principle. The pictures of electronic band structure show the relatively large dispersion near the maximum value of valence band in the directions of Γ-M and Γ-X, but in the direction of Γ-Z, the band structure is relatively flat, and the top of valence band is mainly composed of Cu-Ch anti-bond state which has a very significant impact on the transport performance of p-type SrCuChF. Base on the semiclassical Boltzmann transport theory, we find that the p-type SrCuChF has a high value of Seebeck coefficient due to the quasi-flat character of the electronic bands at the edges of the valence band, and the outstanding anisotropic properties due to their natural layered structure. According to the predicted maximum value of power factors, the optimal doping concentration is presented. Therefore, we give a natural layered structure complex SrCuChF with the good thermoelectric properties and may find many important applications in the thermoelectric functional materials.