Modeling of the Transport Properties of SNS Contacts for Strong Electron-Phonon Interactions

Abstract

A modified expression for the Andreev reflection coefficient is derived taking into account strong electronphonon interactions. A dependence of the superconducting order parameter ∆_σ is numerically modeled for magnesium diboride. The current-voltage characteristics and the dI/dV spectra of the dynamic conductivity of superconductor-normal metal-superconductor (SNS) contacts based on strongly coupled superconductors are calculated for the Averin–Bardas model using the modified Andreev reflection coefficient (on an example of magnesium diboride). Calculations are performed for the mode of high transparency (0.9–0.98). The special features of the SNS contacts based on strongly coupled superconductors are shown.