de Haas-van Alphen Effect in p-Type PbTe and n-Type PbS

A study of the de Haas-van Alphen oscillations in the magnetic susceptibility has been carried out in p-type PbTe and n-type PbS. Measurements have been made on oriented single crystal samples with carrier concentrations of the order of 1018/cm3 in pulsed magnetic fields up to 125 kgauss. The results for p-type PbTe indicate that the valence bands have a maximum at k=0, and four equivalent maxima at the {111} Brillouin zone faces. The 〈111〉 ellipsoids have a longitudinal mass to transverse mass ratio of 6.4±0.3. From the temperature dependence of the amplitude of the oscillations we obtain a value of 0.043±0.006 m0 for the transverse effective mass. The data indicate that the (000) maximum and the (111) maxima lie within 0.002±0.002 ev of each other. The data also indicate an effective broadening temperature of about 8°K which is attributed to inhomogeneities in the carrier concentrations in the samples investigated. Preliminary results on n-type PbS show a single isotropic Fermi surface cross section with a cyclotron mass of 0.14±0.04m0. The direct and indirect optical interband transitions are discussed in the light of these results.