Effects of Quantum-Well Inversion Asymmetry on Electron-Nuclear Spin   Coupling in the Fractional Quantum Hall Regime
  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. 
Katsushi Hashimoto, Koji Muraki, Norio Kumada, Tadashi Saku, and   Yoshiro Hirayama