Crystallochemical analysis of In behaviour in PbTe

The causes of PbTe property change during its alloying with indium have been investigated by the crystallochemical analysis and the analysis of electronic states participating in chemical bond. It is concluded, that some In atoms in Te can be in a shifted location relatively to the lattice points due to the possibility of assymmetric overlap of In and Te p-states. Spanning peculiarities of internal and external s-states in this case permit the atoms display donor properties. It comes out from the analysis of the lattice period change in PbTe-InTe alloys depending on the composition, that In atom quantity, shifted from the points, exceeds the number of atoms in the points, that stipulates n-type of conductivity. Asymmetric location of In atoms causes the possibility of its p-state overlap with Te states by the type of π-bond formation, that increases the probability of In atom position in the shifted location and its donor activity in inform compression