  We examine spin-dependent displacement of a single electron, resulting in
separation and relocation of the electron wavefunction components, and thus
charge parts, corresponding to opposite spins. This separation is induced by a
pulse of an electric field which generates varying Rashba type spin-orbit
coupling. This mechanism is next implemented in a nanodevice based on a gated
quantum dot defined within a quantum nanowire. The electric field pulse is
generated by ultrafast changes of voltages, of the order of several hundred mV,
applied to nearby gates. The device is modeled realistically with appropriate
material parameters and voltages applied to the gates, yielding an accurate
confinement potential and Rashba coupling. At the end, we propose a
spin-to-charge conversion device, which with an additional charge detector will
allow for electron spin state measurement.
