Effect of local field correction in screening dependence of superconducting state parameters for Be₉₀Al₁₀ and Be₇₀Al₃₀ metallic glasses

Abstract

The superconducting state parameters (SSP) viz. electron-phonon coupling strength (λ), Coulomb pseudopotential (µ *), transition temperature (T c ), isotope effect exponent (α) and interaction strength (N 0 V) for two metallic glasses, i.e. Be 90 Al 10 and Be 70 Al 30 , have been investigated by extending the BCSEliasberg-McMillan formalism for the metallic glass superconductors incorporating the effect of local field correction in dielectric screening functions which in turn become prominent in determining superconducting state parameters of the metallic glasses under consideration. We have employed eleven forms of dielectric screening functions -viz. Hartree, RPA, Modified Hubbard, Overhauser, Geldart -Vosko, Animalu, King -Cutler, SCS, Vashistha -Singwi, Ichimaru -Utsumi, and Farid et al. -in conjunction with Ashcroft's potential to predict superconducting state parameters. It is observed that the values of SSP are quite sensitive to the form of dielectric screening functions. In conclusion the present computed values of SSP for the RPA form of dielectric screening are in good agreement with the experimental values and other theoretical results for both glassy materials, which confirms the validity of the proposed formalism.