  A nanodevice capable of separating spins of two electrons confined in a
quantum dot formed in a gated semiconductor nanowire is proposed. Two electrons
confined initially in a single quantum dot in the singlet state are transformed
into the system of two electrons confined in two spatially separated quantum
dots with opposite spins. In order to separate the electrons' spins we exploit
transitions between the singlet and the triplet state which are induced by
resonantly oscillating Rashba spin-obit coupling strength. The proposed device
is all electrically controlled and the electron spin separation can be realized
within tens of picoseconds. The results are supported by solving numerically
quasi-one-dimensional time-dependent Schroedinger equation for two electrons,
where the electron-electron correlations are taken into account in the exact
manner.
