THE INFLUENCE OF HEAVY DOPING BY Cu DONOR IMPURITIES OF THE p-TiCoSb INTERMETALLIC SEMICONDUCTOR ON THE ELECTRONIC STRUCTURE AND ELECTROPHYSICAL PROPERTIES

摘要

The calculations of band structure, disribution of the electronic density of states (DOS), and position of the Fermi level in the p-TiCoSb intermetallic semiconductor caused by its doping with donor impurity by means of substituting the Cu atoms for the Sb ones were carried out. The structure characteristics, temperature and concentration dependencies of the resistivity, magnetic susceptibility, and Seebeck coefficient in the TiCo$_{1 - x}$Cu$_{x}$Sb solid solution were investigated. The predicted transition of conductivity insulator-metal (Anderson transition) was found experimentally. The presence of the magnetic ordering at the dielectric side of the transition, the Pauli paramagnetism susceptibility behavior at the metallic one, substantial noncoincidence in values of activation energy, inferred both from the high temperature linear section of conductivity and thermopower were explained in terms of the model of a heavy doped and strongly compensated semiconductor viewed as an amorphous semiconductor.