Theoretical investigation of superconductivity in MgB2-xCx alloys

In this paper we investigated the superconducting properties of MgB2-xCx alloys where x is the concentration (0.0, 0.03, 0.11 and 0.20). The superconducting state parameters, namely, the electron-phonon coupling strength (λ), Coulomb pseudopotential (μ*), transition temperature (Tc), isotope effect exponent (α) and interaction strength (NoV) of MgB2-xCx alloys have been investigated in the BCS-Eliashberg-McMillan framework, as modified for MgB2-xCx alloys. Pseudo ions with average properties have been considered to replace different types of ions in the system. It is observed that all the superconducting parameters go on decreasing as the concentration of C is increased. The magnitudes of λ and Tc indicate that MgB2-xCx is strong-to-intermediate coupling superconductor. It is also observed that Tc is composition dependent. Present computations yield almost linear variation of Tc with concentration x of C in the MgB2-xCx system, which is in agreement with the experimental data. A linear Tc equation is prop...