Tunneling spectroscopy of single-crystal Pb1−xSnxTe (x=0, 0.2, 0.3)

Abstract

Dependences of the band structure and phonon energies in Pb1−xSnxTe on a tin concentration x were studied by the tunneling measurements using the Pb-SiO2-Pb1−xSnxTe (x=0, 0.2, 0.3) junctions at 4.2 K. From these results, it was found that the value of the energy gap Eg in Pb1−xSnxTe decreased with increasing tin concentration x obeying Eg=180−480x +0.43T meV. This agreed with the results of the optical measurements. The phonon energies in Pb1−xSnxTe were independent of the tin concentrations within the experimental error. No phenomenon accompanying the cubic-rhombohedral phase transition was found, such as a change in the band structure and a phonon softening.