Crossed Andreev reflection at spin-active interfaces

With the aid of the quasiclassical Eilenberger formalism we develop a theory of nonlocal electron transport across three-terminal ballistic normal-superconducting-normal (NSN) devices with spin-active NS interfaces. The phenomenon of crossed Andreev reflection (CAR) is known to play the key role in such transport. We demonstrate that CAR is highly sensitive to electron spins and yields a rich variety of properties of nonlocal conductance which we describe nonperturbatively at arbitrary voltages, temperature, spin-dependent interface transmissions, and their polarizations. Our results can be applied to multiterminal hybrid structures with normal, ferromagnetic, and half-metallic electrodes and can be directly tested in future experiments.