Interchain Coupling in Quasi-One-Dimensional Superconductors: Homogeneous Coupling and Cross-Linking

Abstract

In quasi-one-dimensional superconductors a finite amount of electron tunneling between chains is essential to couple the superconducting order parameters on adjacent chains and to obtain thereby a nonzero transition temperature. This paper uses a microscopically derived Ginzburg-Landau theory to investigate the relation between the electron interchain tunneling and the order parameter coupling. Both a homogeneously coupled system and chains cross-linked by randomly distributed short circuits are considered. Application of the theory to (TMTSF) ₂PF₆, shows that a reasonable concentration of short circuits may considerably increase the interchain coupling and may therefore explain the large increase of the transition temperature observed in recent experiments with GaSb-contacts.