Coherent Propagation of Spin Helices in a Quantum-Well Confined Electron Gas

Luyi Yang, J. D. Koralek, J. Orenstein, D. R. Tibbetts, J. L. Reno, and M. P. Lilly

Phys. Rev. Lett. 109, 246603 – Published 12 December 2012

Abstract

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 $70 V {cm}^{- 1}$ .

Received 22 August 2012

DOI:https://doi.org/10.1103/PhysRevLett.109.246603

Authors & Affiliations

Luyi Yang^1,2, J. D. Koralek², J. Orenstein^1,2, D. R. Tibbetts³, J. L. Reno³, and M. P. Lilly³

¹Department of Physics, University of California, Berkeley, California 94720, USA
²Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
³Sandia National Laboratories, Albuquerque, New Mexico 87123, USA