Effect of annealing on the electrical properties of Pb$_{1-x}$Mn$_x$Te single crystals with excess tellurium

The electrical conductivity $\sigma$, Hall coefficients $R$, and thermopower $\alpha$ of Pb$_{0.96}$Mn$_{0.04}$Te (Te) single crystals annealed at 573 K for 120 h are investigated. It is shown that, in contrast to unannealed samples, the investigated samples exhibit $n$-type conductivity and metal-type dependences $\sigma(T)$ in the temperature range 77–300 K. It is suggested that, upon annealing, a portion of the excess tellurium atoms occupy vacancies in the lead sublattice with the formation of new vacancies in the tellurium sublattice of the samples.