  We show that noncollinear Andreev reflections can be induced at interfaces of
semiconductor nanowires with spin-orbit coupling, Zeeman splitting and
proximity-induced superconductivity. In a noncollinear local Andreev
reflection, the spin polarizations of the injected and the retro-reflected
carriers are typically at an angle which is tunable via system parameters.
While in a nonlocal transport, this noncollinearity enables us to identify and
block, at different voltage configurations, the noncollinear cross Andreev
reflection and the direct charge transfer processes. We demonstrate that the
intriguing noncollinearity originates from the spin-dependent coupling between
carriers in the lead and the lowest discrete states in the wire, which, for a
topological superconducting nanowire, are related to the overlap-induced
hybridization of Majorana edge states in a finite system. These interesting
phenomena can be observed in semiconductor nanowires of experimentally relevant
lengths, and are potentially useful for spintronics.
