Electronic structure of (Tl0.125Pb0.875)Te

We present an ab-initio supercell calculation of electronic band structures of (TlδPb1−δ)Te with δ = 0 and 0.125. PbTe is to be a very small gap semiconductor, and Tl doping induces a quasi-impurity band in this in-gap state. A local relaxation based on ionic model is discussed.