Oscillations of transport properties in PbTe–Bi2Te3 solid solutions

Abstract

The concentration dependences of the electrical conductivity σ, Hall coefficient RH, charge carrier mobility μH, and Seebeck coefficient S for (PbTe)100−x(Bi2Te3)x semiconductor alloys were obtained at room temperature. It was found that within the PbTe-based solid solution region (x=0–6), the concentration dependences of σ, RH, μH, and S exhibit unusual for solid solutions non-monotonic oscillatory behavior, which indicates qualitative changes in the defect subsystem of the crystal occurring under increasing Bi2Te3 concentration. The observed peculiarities are attributed to the percolation effects and to the self-organization processes in the solid solutions caused by the interactions of impurity atoms among themselves and with atoms of the host lattice. It is suggested that the observed effects are typical for solid solutions, and the probability of their manifestation depends on the crystal structure, elastic and other properties of the solid solution constituents.