Superconductivity in tight-binding approximation

Abstract

An interpretation of Barišić's relation for transition elements between the d-electron contribution to the cohesive energy and the local atomic parameter η is presented. We extend this relation to a lattice with more than one atom per unit cell in the tight-binding approximation of rigid ions. It is conjectured that Barišić's relation is correct to first order approximation for transition metal alloys, provided the phonon induced d- d coupling is the dominant mechanism for superconductivity.