Dethlefsen, A. F. and Mariani, E. and Tranitz, Hans-Peter and Wegscheider, Werner and Haug, R. J.
Signatures of spin in the ν=1∕3 fractional quantum Hall effect.
Physical Review B (PRB) 74 (16), p. 165325.
The activation gap Δ of the fractional quantum Hall state at constant filling ν=1∕3 is measured in a wide range of perpendicular magnetic field B. Despite the full spin polarization of the incompressible ground state, we observe a sharp crossover between a low-field linear dependence of Δ on B and a Coulomblike square root behavior at large B. From the global gap reduction we get information about the mobility edges in the fractional quantum Hall regime.