Nonequilibrium transport in density-modulated phases of the second   Landau level
  We investigate non-equilibrium transport in the reentrant integer quantum Hall phases of the second Landau level. At high currents, we observe a transition from the reentrant integer quantum Hall phases to classical Hall-conduction. Surprisingly, this transition is markedly different for the hole- and electron sides of each spin-branch. While the hole bubble phases exhibit a sharp transition to an isotropic compressible phase, the transition for the electron side occurs via an intermediate phase. This might indicate a more complex structure of the bubble phases than currently anticipated, or a breaking of the particle-hole symmetry. Such a symmetry breaking in the second Landau level might also have consequences for the physics at filling factor $\nu$=5/2. 
S. Baer, C. R\"ossler, S. Hennel, H.C. Overweg, T. Ihn, K. Ensslin, C.   Reichl, and W. Wegscheider
cond-mat.mes-hall