"Random walk approach to spin dynamics in a two-dimensional electron gas with spin-orbit coupling"

Luyi Yang: J. Orenstein, and Dung-Hai Lee ; Phys. Rev. B, 10/26/10.

Additional Authors: J. Orenstein, and Dung-Hai Lee

Abstract:

We introduce and solve a semiclassical random walk (RW) model that describes the dynamics of spin polarization waves in zinc-blende semiconductor quantum wells. We derive the dispersion relations for these waves, including the Rashba, linear and cubic Dresselhaus spin-orbit interactions, as well as the effects of an electric field applied parallel to the spin polarization wave vector. In agreement with calculations based on quantum kinetic theory [ P. Kleinert and V. V. Bryksin Phys. Rev. B 76 205326 (2007)], the RW approach predicts that spin waves acquire a phase velocity in the presence of the field that crosses zero at a nonzero wave vector, q0. In addition, we show that the spin-wave decay rate is independent of field at q0 but increases as (q−q0)2 for q≠q0. These predictions can be tested experimentally by suitable transient spin grating experiments.