Theoretical study of superconducting parameters of Al and Li Co-doping substitution on MgB2

Abstract

In the present study we investigated the theoretical calculation of Superconducting state parameters by Al as electron doping and Li as hole co-doping on MgB2 superconductor for four different concentrations (Mg0.962Al0.018Li0.02B2, Mg0.854Al0.096Li0.05B2, Mg0.812Al0.138Li0.05B2, Mg0.77Al0.14Li0.09B2). The well-known Empty Core (EMC) model of Ashcroft potential was used to study the theoretical investigation of the superconducting state parameters (SSP) viz. Electron–Phonon Coupling Strength (λ), Coulomb Pseudopotential (µ*), Transition Temperature (Tc), Isotope Effect Exponent (α) and Effective Interaction Strength (N0V) of Mg1-x-yAlxLiyB2 system. It is observed that addition of Al & Li doping to superconductor MgB2 causes the parameters λ, Tc, α and N0V decreases. This suggests decrease in superconducting behaviour of MgB2 is due to effect of Al and Li co-doping in MgB2 which also shows strong coupling to intermediate coupling behaviour. Whereas Coulomb Pseudopotential (µ*) remains approximately same. In this paper it is also observed that Transition Temperature (Tc) for Mg1-x-yAlxLiyB2 alloys for different concentration is almost same with the experimental values.