  We theoretically consider spin pumping in a junction between a ferromagnetic
insulator (FI) and a two-dimensional electron gas (2DEG) in which the Rashba
and Dresselhaus spin-orbit interactions coexist. Using second-order
perturbation theory, we derive an increase in linewidth in the case of an
interfacial exchange coupling in a ferromagnetic resonance (FMR) experiment. We
clarify how the enhancement of Gilbert damping depends on the resonant
frequency and spin orientation of the FI. We show that this setup of an FMR
experiment can provide information on the spin texture of 2DEG at the Fermi
surface.
