Anomalous band Gap evolution from band inversion in Pb1-xSnxTe nanocrystals.

We report the synthesis of a series of narrowly disperse Pb(1-x)Sn(x)Te nanocrystals by employing a colloidal synthetic strategy. As synthesized nanocrystals are solid solutions with cubic NaCl-type structure and exhibit band energy gaps in the mid-IR region. We show that these ternary nanocrystals display qualitatively the same anomalous trend in band gaps as a function of x that is attributed to the band inversion phenomenon of the corresponding bulk materials; however unlike the bulk the band gap does not vanish at any Sn concentration but achieves a minimum of 0.28 eV for x = 0.67.