Recently a class of systems, AgSbPb2n-2Ten, was found to be excellent high temperature thermo-electrics. Since electronic properties of semiconductors in general and thermoelectric behavior in particular, were dominated by defects, ab initio electronic structure calculations of Ag and Sb substitutional defects in PbTe were carried out. It was found that these defects gave rise to deep defect states and that the electronic structure near to the gap depended sensitively upon the micro structural arrangements of these defects. The modified electronic structure may be responsible for the observed high temperature thermoelectric properties of the above compounds.

Electronic Structure of Defects and Defect Clusters in Narrow Band-Gap Semiconductor PbTe. S.D.Mahanti, D.Bilc: Journal of Physics - Condensed Matter, 2004, 16[44], S5277-88