Zhu Z.-G. and Berakdar J.

We investigate the spin-dependent dynamical response of a quantum ring with a spin orbit SO interaction upon the application of linearly polarized, picosecond, asymmetric electromagnetic pulses. The oscillations of the generated dipole moment are sensitive to the parity of the occupation number in the ring and to the strength of the SO coupling. It is shown how the associated emission spectrum can be controlled via the pulse strength or a gate voltage. In addition, we inspect how a static magnetic flux can modify the nonequilibrium dynamics. In the presence of the SO interaction and for a paramagnetic ring, the applied pulse results in a spin-split, nonequilibrium local charge density. The resulting temporal spin polarization is directed perpendicular to the light-pulse-polarization axis and oscillates periodically with the frequency of the spin-split charge density. The spin-averaged, nonequilibrium charge-density possesses a left-right symmetry with respect to the pulsepolarization axis. The calculations presented here are applicable to nanometer rings fabricated in heterojuctions of III-V and II-VI semiconductors containing several hundreds of electrons.

PDF (839kB)

(For personal use only. Please send an email to our secretary if you need the paper.)