Experimental observation of band inversion in the PbSnTe system

The band inversion in the PbSnTe compound has been observed by optical and electrical measurements. The samples, high quality Pb1-xSnxTe epitaxial lay ers, have been grown by molecular-beam epitaxy on (111)BaF2 substrates. Opt ical transmission measurements have revealed a change in signal of the ener gy gap temperature derivative for samples with 0.35 < x < 0.70. In the same samples and at the same temperature, a minimum in the resistivity has been observed, showing a interrelation between the optical and electrical measu rements. However, the temperature, for which the inversion occurs, is not t hat predicted by the band inversion model. This discrepancy is supposed to be due to the relatively high hole concentration of these samples. (C) 1999 American Institute of Physics. [S0021-8979(99)08624-7].