We have studied the quasiparticle excitation spectrum of the superconductor Ba8Si46 by local tunneling spectroscopy. Using high energy resolution achieved in Superconductor-Superconductor junctions we observed tunneling conductance spectra of a non-conventional shape revealing two distinct energy gaps, DeltaL = 1.3meV and DeltaS = 0.9meV. The analysis of tunneling data evidenced that DeltaL is the principal superconducting gap while DeltaS, smaller and more dispersive, is induced into an intrinsically non-superconducting band of the material by the inter-band quasiparticle scattering.
@article{arxiv.1002.3695,
title = {Evidence for Scattering-Dependent Multigap Superconductivity in Ba8Si46},
author = {Yves Noat and Tristan Cren and Pierre Toulemonde and Alfonso San Miguel and Francois Debontridder and Vincent Dubost and Dimitri Roditchev},
journal= {arXiv preprint arXiv:1002.3695},
year = {2010}
}