Spin dynamics of optically excited electrons confined in asymmetric coupled quantum wells are investigated through time resolved Faraday rotation experiments. The inter-well coupling is shown to depend on applied electric field and barrier thickness. We observe three coupling regimes: independent spin precession in isolated quantum wells, incoherent spin transfer between single-well states, and coherent spin transfer in a highly coupled system. Relative values of the inter-well tunneling time, the electron spin lifetime, and the Larmor precession period appear to govern this behavior.
@article{arxiv.cond-mat/0406668,
title = {Spin transfer and coherence in coupled quantum wells},
author = {M. Poggio and G. M. Steeves and R. C. Myers and N. P. Stern and A. C. Gossard and D. D. Awschalom},
journal= {arXiv preprint arXiv:cond-mat/0406668},
year = {2007}
}