Real-time dynamics of spin-dependent transport through a double-quantum-dot Aharonov-Bohm interferometer with spin-orbit interaction

摘要

The spin-resolved non-equilibrium real-time electron transport through adouble-quantum-dot (DQD) Aharonov-Bohm (AB) interferometer with spin-orbitinteraction (SOI) is explored. The SOI and AB interference in the real-timedynamics of spin transport is expressed by effective magnetic fluxes.Analytical formulae for the time-dependent currents, for initially unpolarizedspins, are presented. In many cases, there appear spin currents in theelectrodes, for which the spins in each electrode are polarized alongcharacteristic directions, pre-determined by the SOI parameters and by thegeometry of the system. Special choices of the system parameters yieldsteady-state currents in which the spins are fully polarized along thesecharacteristic directions. The time required to reach this steady state dependson the couplings of the DQD to the leads. The magnitudes of the currents dependstrongly on the SOI-induced effective fluxes. Without the magnetic flux, thespin-polarized current cannot be sustained to the steady states, due to thephase rigidity for this system. For a non-degenerate DQD, transient spintransport can be produced by the sole effects of SOI. We also show that one canextract the spin-resolved currents from measurements of the total chargecurrent.