Rashba Spin-Orbit Interaction and Shot Noise for Spin-Polarized and Entangled Electrons

We study shot noise for spin-polarized currents and entangled electron pairs in a four-probe (beam-splitter) geometry with a local Rashba spin-orbit ($s\mathrm{\text{−}}o$) interaction in the incoming leads. Within the scattering formalism we find that shot noise exhibits Rashba-induced oscillations with continuous bunching and antibunching. We show that entangled states and triplet states can be identified via their Rashba phase in noise measurements. For two-channel leads, we find an additional spin rotation due to $s\mathrm{\text{−}}o$ induced interband coupling which enhances spin control. We show that the $s\mathrm{\text{−}}o$ interaction determines the Fano factor, which provides a direct way to measure the Rashba coupling constant via noise.