Interband interactions and three-square-well potentials on the superconductivity of MgB2

✍ Scribed by Obinna C. Abah; G.C. Asomba; C.M.I. Okoye

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 868 KB
• Volume: 149
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/j.ssc.2009.06.014

✦ Synopsis

a b s t r a c t Superconductivity in magnesium diboride, MgB 2 , is described within the framework of Bogoliubov-Valatin two-band and two-gap formalism, employing a three-square-well potential model. The expressions for the superconducting transition temperature, T c , and the isotope exponent, β, are derived. Numerical calculations with the expressions newly reproduce near-experimental T c (=38.50 K) and β (=0.38). The influences of the interband attractive electron-acoustic (λ π σ ) and electron-optical (k πσ ) phonons as well as repulsive Coulomb pseudopotential (µ * π σ ) on T c and β are sketched. It is concluded that λ π σ and k π σ have near-identical elevating effects on T c and β but µ * π σ has reverse effects, similar to the effect of interband impurity scattering.