Thermoelectric response of fractional quantized Hall and re-entrant   insulating states in the N=1 Landau level
  Detailed measurements of the longitudinal thermopower of two-dimensional electrons in the first excited Landau level are reported. Clear signatures of numerous fractional quantized Hall states, including those at $\nu = 5/2$ and 7/3, are observed in the magnetic field and temperature dependence of the thermopower. An abrupt collapse of the thermopower is observed below about $T= 40$ mK at those filling factors where re-entrant insulating electronic states have been observed in conventional resistive transport studies. The thermopower observed at $\nu = 5/2$ is discussed in the context of recent theories which incorporate non-abelian quasiparticle exchange statistics. 
W.E. Chickering, J.P. Eisenstein, L.N. Pfeiffer, and K.W. West
cond-mat.mes-hall