Noise of Spin-Polarized Currents at a Beam Splitter with Local Spin–Orbit Interaction.

An electronic beam splitter with a local Rashba spin–orbit coupling can serve as a detector for spin-polarized currents. The spin–orbit coupling plays the role of a tunable spin rotator and can be controlled via a gate electrode on top of the conductor. We use spin-resolved scattering theory to calculate the zero-temperature current fluctuations (shot noise) for such a four-terminal device and show that the shot noise is proportional to the spin polarization of the source. Moreover, we analyze the effect of spin–orbit-induced intersubband coupling, leading to an additional spin rotation. [ABSTRACT FROM AUTHOR]