Impact of disorder on the 5/2 fractional quantum Hall state
  We compare the energy gap of the \nu=5/2 fractional quantum Hall effect state obtained in conventional high mobility modulation doped quantum well samples with those obtained in high quality GaAs transistors (heterojunction insulated gate field-effect transistors). We are able to identify the different roles that long range and short range disorders play in the 5/2 state and observe that the long range potential fluctuations are more detrimental to the strength of the 5/2 state than short-range potential disorder. 
W. Pan, N. Masuhara, N.S. Sullivan, K.W. Baldwin, K.W. West, L.N.   Pfeiffer, and D.C. Tsui
cond-mat.mes-hall