  We apply the scattering matrix approach to the triplet proximity effect in
superconductor-half metal structures. We find that for junctions that do not
mix different orbital modes, the zero bias Andreev conductance vanishes, while
the zero bias Josephson current is nonzero. We illustrate this finding on a
ballistic half-metal--superconductor (HS) and superconductor -- half-metal --
superconductor (SHS) junction with translation invariance along the interfaces,
and on HS and SHS systems where transport through the half-metallic region
takes place through a single conducting channel. Our calculations for these
physically single mode setups -- single mode point contacts and chaotic quantum
dots with single mode contacts -- illustrate the main strength of the
scattering matrix approach: it allows for studying systems in the quantum
mechanical limit, which is inaccessible for quasiclassical Green's function
methods, the main theoretical tool in previous works on the triplet proximity
effect.
