New Model for Vacancy States in PbTe

Abstract

We present new results that the states associated with Pb or Te vacancies in PbTe lie well up in the conduction band and that no localized states appear in the valence-conduction band gap. Holes and electrons due to Pb or Te vacancies cannot freeze out even at 0\ifmmode^\circ\else\textdegree\fi{}K giving PbTe the character of a metal at very low temperatures.