Spin dynamics in the strong spin-orbit coupling regime

We study the spin dynamics in a high-mobility two-dimensional electron gas with generic spin-orbit interactions (SOI's). We derive a set of spin-dynamics equations that capture purely exponentially the damped oscillatory spin evolution modes observed in different regimes of SOI strength. Hence we provide a full treatment of the D'yakonov-Perel mechanism by using the microscopic linear-response theory from the weak to the strong SOI limit. We show that the damped oscillatory modes appear when the electron scattering time is larger than half of the spin precession time due to the SOI, in agreement with recent observations. We propose a way to measure the scattering time and the relative strength of Rashba and linear Dresselhaus SOI's based on these modes and optical grating experiments. We discuss the physical interpretation of each of these modes in the context of Rabi oscillation.