Polarized spin transport in mesoscopic quantum rings with electron--phonon and Rashba spin--orbit coupling

The influence of electron--phonon (EP) scattering on spinpolarization of current output from a mesoscopic ring with Rashbaspin--orbit (SO) interaction is numerically investigated. There arethree leads connecting to the ring at different positions;unpolarized current is injected to one of them, and the other twoare output channels with different bias voltages. The spinpolarization of current in the outgoing leads shows oscillations as afunction of EP coupling strength owing to the quantum interferenceof EP states in the ring region. As temperature increases, theoscillations are evidently suppressed, implying decoherence ofthe EP states. The simulation shows that the magnitude of polarizedcurrent is sensitive to the location of the lead. The polarizedcurrent depends on the connecting position of the lead in acomplicated way due to the spin-sensitive quantum interferenceeffects caused by different phases accumulated by transmittingelectrons with opposite spin states along different paths.