  We examine effects of inversion asymmetry of a GaAs/Al0.3Ga0.7As quantum well
(QW) on electron-nuclear spin coupling in the fractional quantum Hall (QH)
regime. Increasing the QW potential asymmetry at a fixed Landau-level filling
factor (nu) with gate voltages suppresses the current-induced nuclear spin
polarization in the nu = 2/3 Ising QH ferromagnet, while it significantly
enhances the nuclear spin relaxation at general nu. These findings suggest that
mixing of different spin states due to the Rashba spin-orbit interaction
strongly affects the electron-nuclear spin coupling.
