  Controlling magnetism through non-magnetic means is highly desirable for
future electronic devices, as such means typically have ultra-low power
requirements and can provide coherent control. In recent years, great
experimental progress has been made in the field of electrical manipulation of
magnetism in numerous material systems. These studies generally do not consider
the directionality of the applied non-magnetic potentials and/or magnetism
switching. Here, we theoretically conceive and experimentally demonstrate a
non-magnetic one-way spin switch device using a spin-orbit coupled
Bose-Einstein condensate subjected to a moving spin-independent dipole
potential. The physical foundation of this unidirectional device is based on
the breakdown of Galilean invariance in the presence of spin-orbit coupling.
Such a one-way spin switch opens an avenue for designing novel quantum devices
with unique functionalities and may facilitate further experimental
investigations of other one-way spintronic and atomtronic devices.
