Anomalous behaviour of thermal e.m.f. and magnetoresistance of thallium-doped lead telluride filamentary crystals

Investigation results of temperature dependences of specific resistance ρ(T), thermo emf α(T) and magnetofield dependences Δρ(B)/ρ0 of pure and thallium-alloyed filamentary lead telluride crystals are presented. Filamentary monocrystals PbTe are prepared by filling quartz microcapillaries with the melt of the composition Pb1-xTlxTe (x=0.0025 at % with its subsequent crystallization. The value of specific resistance of the monocrystals studied shows that conductivity in PbTe is conditioned by impurity charge carriers which, in its turn, testifies to the fact that the charge of sign and negative value thermo emf in the range of low temperatures (T <or approx. 100 K) can not be associated with transition to intrinsic conductivity, where electron contribution will be much higher at the expense of a higher mobility