Landau level spin diode in a GaAs two dimensional hole system
  We have fabricated and characterized the Landau level spin diode in GaAs two dimensional hole system. We used the hole Landau level spin diode to probe the hyperfine coupling between the hole and nuclear spins and found no detectable net nuclear polarization, indicating that hole-nuclear spin flip-flop processes are suppressed by at least three orders of magnitude compared to GaAs electron systems. 
O. Klochan, A. R. Hamilton, K. das Gupta, F. Sfigakis, H. E. Beere, D.   A. Ritchie
cond-mat.mes-hall