Thermoelectric properties of heterogeneous, many-phase and composite materials

The model of formation of the thermoelectric properties of inhomogeneous materials and the system classification of different structural classes and types of the materials is worked out. The analysis of the concentration dependences of thermoelectric properties is performed on the basis of this method. It is found that the thermoelectric properties of inhomogeneous materials are connected with their composition and internal structural characteristics (such as the coefficient of leakage, the leakage threshold, the contact potential difference and the coefficients of skeletonivity, matrixivity, chainivity). The principal possibility of getting a higher thermoelectric figure of merit (TFM), Z, (in comparison with that of the initial material components) is shown. Such a possibility has been realized in the systems Bi₂Te₃-C, MnSi_1.73 -CaF as well as in some composite materials, the most essential increase of the TFM being attained in cascade materials