Features of vanadium impurity states in lead telluride

Temperature dependences of resistivity, magnetic susceptibility, and charge-carrier concentration and mobility in single-crystalline PbTe:V samples with a varied impurity content are investigated. It is shown that vanadium forms a donor level located ∼20 meV below the conduction-band bottom. The electron mobility is as high as 10 5 cm 2 V −1 s −1 in the samples with N V ≤ 0.21 at % and proves to be more than an order of magnitude higher in the samples with the highest vanadium content N V = 0.26 at %. In the same samples, the real part of the conductivity is characterized by a pronounced frequency dependence. An increase in vanadium concentration is accompanied by a decrease in the effective magnetic moment of impurity atoms. The features of electron transport in PbTe:V may be caused by a variable vanadium valence and by the effect of interimpurity correlations.