Phase transitions and transport properties in SnTe crystals and thin films

Abstract

The temperature dependences of electrical conductivity (sigma) , Hall coefficient RH and charge carrier mobility (mu) H for tin telluride with different degrees of deviation from stoichiometry have been obtained in the range of 4.2-300K. It has been shown that in bulk and thin film samples with charge carrier concentrations up to pH approximately equals 8 X 10 cm-3 there is observed earlier known ferroelectric phase transition accompanied by anomalous drop in (sigma) and (mu) H in the vicinity of T approximately equals 100 K. On the other hand, as pH grows, there appear temperature anomalies of transport coefficients in the range of 135-150 and 200-215 K. THese anomalies are attributed to the phase transitions connected with cation vacancies redistribution over the crystal lattice with changing temperature. It has been shown that realization of these processes is controlled by charge carrier concentration and kinetic factors.