STRAIN-INDUCED SUPERCONDUCTIVITY IN LEAD SALT SUPERLATTICES

Recent data on lead salt superconducting superlattices are interpreted in terms of an electronic pairing mechanism. The strain in these structures is estimated within the uncertainties in the deformation potential parameters and boundary conditions. The results indicate that the PbS/PbTe superlattice on KCl [100] substrate is particularly susceptible to band inversion in the PbTe layers. Consequently, electrons (or holes) are trapped in the ensuing localized states associated with the PbS/PbTe interface. By virtue of an exciton‐exchange mechanism these electrons condense into a superconducting state. The estimated Tc is in reasonable agreement with the data. Finally the observed superconductivity in another IV–VI superlattice is discussed in light of the present model. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA