Band crossing evidence in PbSnTe observed by optical transmission measurements

Abstract

Using high quality epitaxial layers, we h a ve obtained direct evidence of the band inversion in the P b 1,x Sn x T esystem. The samples, covering the whole composition range, were grown by molecular beam epitaxy on 111 BaF 2 substrates. A minimumin the resistivity as a function of temperature was observed for all samples with Sn composition 0:35 x 0:70. In the same samples and at the same temperature, temperature dependent optical transmission measurements have revealed a change in signal of the energy gap temperature derivative, a direct evidence of the band inversion. However, the temperature for which the inversion occurs is not the one expected by the band inversion model. This discrepancy is supposed to be due to the Burstein-Moss shift caused by the relatively high hole concentration observed in these samples.

Thermodynamic Descriptions for the Sn-Te and Pb-Sn-Te Systems

“…Accordingly, such two binary phases can form a continuous solid solution in the ternary PbSn-Te system, which is treated with a two-sublattice model given by (Pb,Sn,Va) 1 (Te) 1 …”

Optical investigation of the thermoelectric topological crystalline insulatorPb0.77Sn0.23Se

“…Currently, the primary methods of studying thermoelectrics are by DC transport, optics, thermopower experiments and neutron scattering, [6][7][8][9][10][11][12][13][14][15] where the standard Drude model is often employed to extract temperature dependent information about carrier lifetimes. A major shortcoming of the Drude model, however, is the assumption that the carrier lifetime is frequency independent.…”

Effect of hydrostatic pressure and uniaxial strain on the electronic structure ofPb1−xSnxTe

“…There exist various experimental reports on the change of the band gap with concentration x in Pb 1−x Sn x Te 13,14 . It is found that by increasing the concentration of Sn the band gap decreases linearly up to a certain concentration x 0 where the band gap vanishes.…”