Coherent propagation of spin helices in a quantum-well confined electron gas.
We use phase-resolved transient grating spectroscopy to measure the propagation of spin helices in a high mobility n-GaAs/AlGaAs quantum well with an applied in-plane electric field. At relatively low fields helical modes crossover from overdamped excitations where the spin-precession period exceeds the spin lifetime, to a regime of coherent propagation where several spin-precession periods can be observed. We demonstrate that the envelope of a spin polarization packet reaches a current-driven velocity of 10(7) cm s(-1) in an applied field of 70 V cm(-1).
Department of Physics, University of California, Berkeley, California 94720, USA.
Luyi
L
Yang
J D
JD
Koralek
J
J
Orenstein
D R
DR
Tibbetts
J L
JL
Reno
M P
MP
Lilly