In a one-dimensional weak-link wire the spin-orbit interaction (SOI) alone
cannot generate a nonzero spin current. We show that a Zeeman field acting in
the wire in conjunction with the Rashba SOI there does yield such a current,
whose magnitude and direction depend on the direction of the field. When this
field is not parallel to the effective field due to the SOI, both the charge
and the spin currents oscillate with the length of the wire. Measuring the
oscillating anisotropic magnetoresistance can thus yield information on the SOI
strength. These features are tuned by applying a magnetic and/or an electric
field, with possible applications to spintronics.Comment: 6 pages,4 figures, Supplemental materia
