Ballistic spin interferometer using the Rashba effect

We propose a ballistic spin interferometer using a square loop (SL) geometry, where an incident electron wave packet is split into a pair of partial waves by a "hypothetical" beam splitter. These electron partial waves, then, follow the SL path in the clockwise and counterclockwise directions, respectively, so that they interfere with each other at the incident point, retaining the spin degree of freedom. We find that the backscattering probability of an incident electron can be largely modulated by varying the magnitude of the Rashba spin-orbit coupling constant alpha. We propose to make the proposed spin interferometry experiment using an artificial nanostructure fabricated in, for example, In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As quantum wells.