TRANSPORT PHENOMENA IN THE SOLID-SOLUTION (PB0.78SN0.22)(0.97)IN0.03TE IN THE HOPPING CONDUCTION REGION

Data on the electrical conductivity, the thermoelectric power, and the Hall and Nernst-Ettingshausen effects in the temperature range from 7 7 to 400 K for the a solid solution PbTe-SnTe with a high In content ( 3 at. %) and additional doping with chlorine and thallium are presente d. Specifically, the Nernst-Ettingshausen coefficient exhibits propert ies which are unusual for IV-VI semiconductors: It is positive and dec reases rapidly with increasing temperature. The experimental data are discussed on the basis of a model in which the main transport mechanis m is hopping conduction along strongly localized electronic states of the In impurity. Conduction along delocalized states of the conduction band makes a substantial contribution to the effects observed in a tr ansverse magnetic field. The model gives satisfactory agreement with e xperiment, including the sign, magnitude, and temperature dependence o f the Nernst-Ettingshausen coefficient. (C) 1998 American Institute of Physics.