Proposed Nonmagnetic Stern-Gerlach Experiment Using Electron Diffraction

We demonstrate that a transverse spin current can be generated simply by diffraction through a single slit in the spin-orbit coupling system of the two-dimensional electron gas. In the regime of spin-orbit coupling ~10^-13 eV·m, an out-of-plane component of the electron spin of up to 0.42 can be generated. Based on this effect, a novel device consisting of a grating to distill spin is designed. Two first diffraction peaks of electron carry different spins, providing a nonmagnetic version of the Stern-Gerlach experiment. The direction of the spin current can be controlled by the gate voltage with low energy cost.