A one-dimensional spin-orbit interferometer

We demonstrate that the combination of an external magnetic field and the intrinsic spin-orbit interaction results in nonadiabatic precession of the electron spin after transmission through a quantum point contact (QPC). We suggest that this precession may be observed in a device consisting of two QPCs placed in series. The pattern of resonant peaks in the transmission is strongly influenced by the non-abelian phase resulting from this precession. Moreover, a novel type of resonance which is associated with suppressed, rather than enhanced, transmission emerges in the strongly nonadiabatic regime. The shift in the resonant transmission peaks is dependent on the spin-orbit interaction and therefore offers a novel way to directly measure these interactions in a ballistic 1D system.