Nanomechanical spin-polarizer

We study the effects of time dependent strain on transport properties in a long semiconductor rod and predict a piezo-spin effect. Torsional oscillations of a free-standing semiconductor beam are shown to cause spin-dependent oscillating with time potentials that spin-polarize an applied charge current in the presence of intentional or disorder scattering potentials. One can apply AC voltage synchronized with the mechanical motion to obtain a DC spin current. The thus created spin accumulation in the leads can be detected by e.g. ferromagnetic side contact or by the optical Kerr rotation. We propose to build the mechanical spin generators and manipulators based on the piezo-spin effect.