TRANSPORT-PROPERTIES ANALYSIS OF SINGLE-CRYSTALS (BIXSB1-X)2TE3 GROWNBY THE TRAVELING HEATER METHOD

A modeling of the transport properties of p-type (BixSb1-x)2 Te3 singl e crystals is presented. Reasonably good agreement between calculated and experimental transport coefficients was achieved by considering a single valence band and acoustic phonon and ionized impurity scatterin g for holes. The anisotropy of the transport coefficients, in directio ns perpendicular (11) and parallel (33) to the trigonal c-axis of the crystals, was also taken into account in the model. The effective mass es m(ij) the isotropic and anisotropic energy independent relaxation t ime factors tau(oac) and tau(oionii) for the main directions (ii = 11 or 33) were determined for two solid solutions with x = 0.2 and 0.25. The lattice thermal conductivities were estimated for the two solid so lutions. The maximum room temperature figure of merit was estimated at 3.2 x 10(-3) K-1 for a solid solution with x = 0.225 in good agreemen t with the experimental results.