  Spin and charge currents can be generated by an ac voltage through a
one-channel quantum wire with strong electron interactions in a static uniform
magnetic field. In a certain range of low voltages, the spin current can grow
as a negative power of the voltage bias as the voltage decreases. The spin
current expressed in units of hbar/2 per second can become much larger than the
charge current in units of the electron charge per second. The system requires
neither spin-polarized particle injection nor time-dependent magnetic fields.

Mesoscale and Nanoscale Physics;Strongly Correlated Electrons