Observation of Incompressibility at $\nu=4/11$ and $\nu=5/13$
  The region of filling factors $1/3<\nu<2/5$ is predicted to support new types of fractional quantum Hall states with topological order different from that of the Laughlin-Jain or the Moore-Read states. Incompressibility is a necessary condition for the formation of such novel topological states. We find that at 6.9~mK incompressibility develops only at $\nu=4/11$ and $5/13$, while the states at $\nu=6/17$ and $3/8$ remain compressible. Our observations at $\nu=4/11$ and $5/13$ are first steps towards understanding emergent topological order in these fractional quantum Hall states. 
N. Samkharadze, I. Arnold, L.N. Pfeiffer, K.W. West, and G.A. Cs\'athy
cond-mat.str-el cond-mat.mes-hall