SPONTANEOUS SPIN POLARIZATION OF BALLISTIC ELECTRONS IN SINGLE-MODE QUANTUM WIRES DUE TO SPIN SPLITTING

We show that a quantum-wire device with spin splitting can work as an active spin polarizer. Hot electrons in one ''spin'' subband (e.g., ''spin up'') may pass such a device with weak electron pair scattering, while electrons in the opposite subband (''spin down'') may have high conversion probability into the spin-up subband, resulting in spin polarization of a hot electron beam. Under different circumstances a hot electron beam passing through a single-mode quantum wire may induce a steady state magnetization of the background electron gas in a section of the wire weakly coupled to the environment.