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Interorbital pair scattering in two-band superconductors

2009; American Physical Society; Volume: 80; Issue: 22 Linguagem: Inglês

10.1103/physrevb.80.224523

1550-235X

A. Ciechan, K. I. Wysokiński,

Physics of Superconductivity and Magnetism

The calculations of local and global properties of two-band superconductors have been presented with particular attention paid to the role of the interorbital scattering of pairs. The properties of such superconductors are very different from a single-band or typical two-band systems with dominant intraband pairing interactions. The effect of the Van Hove singularity in one of the bands on the properties of the intraband clean superconductor has been discussed. It leads to marked increase in superconducting transition temperature in the weak-coupling limit. We also study the inhomogeneous systems in which characteristics change from place to place by solving the Bogolubov-de Gennes equations for small clusters. Suppression of the superconducting order parameter by the single impurity scattering fermions between two orbitals is contrasted with that due to intraorbital impurity scattering. The results obtained for impure systems have been shown as maps of local density of states, order parameter, and gap function. They can be directly compared with the scanning tunneling microscope spectra of real material.