Tp. Devereaux et P. Fulde, MULTIPLE ANDREEV SCATTERING IN SUPERCONDUCTOR NORMAL-METAL SUPERCONDUCTOR JUNCTIONS AS A TEST FOR ANISOTROPIC ELECTRON PAIRING, Physical review. B, Condensed matter, 47(21), 1993, pp. 14638-14641
Current-voltage characteristics of superconductor-normal metal-superco
nductor junctions due to multiple Andreev reflections at the interface
s are investigated for anisotropic superconductors. Using nonequilibri
um time-dependent Bogoliubov-de Gennes equations, it is shown that the
presence of gap nodes perpendicular to the interface greatly smear su
bharmonic gap structures corresponding to voltages V less-than-or-equa
l-to 2DELTA(k)/en for n = 1, 2, 3, ... for n Andreev reflections as se
en in s-wave superconductors, while the overall current due to Andreev
reflections is reduced. Further, asymmetric line shapes for dI/dV are
predicted. It is suggested that these features could be used to disti
nguish between superconductors with or without nodes.