Quantum pumping and rectification effects in Aharonov-Bohm-Casher   ring-dot systems
  We study the time-dependent transport of charge and spin through a ring-shaped region sequentially coupled to a weakly interacting quantum dot in the presence of an Aharonov-Bohm flux and spin-orbit interaction. The time-dependent modulation of the spin-orbit interaction, or of the corresponding Aharonov-Casher flux, together with the modulation of the dot-level induces an electrically pumped spin current even in absence of a charge current. The results beyond the adiabatic regime show that an additional rectification current proportional to \cos(\phi), being \phi the relative phase between the time varying parameters, is generated. We discuss the relevance of such term in connection with recent experiments on out-of-equilibrium quantum dots. 
F. Romeo, R. Citro and M. Marinaro