Signatures of spin in the n=1/3 Fractional Quantum Hall Effect

A. F. Dethlefsen, E. Mariani, H. -P. Tranitz, W. Wegscheider, R. J. Haug

Published 2005-08-17Version 1

The activation gap Delta of the fractional quantum Hall state at constant filling n =1/3 is measured in 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 Delta on B associated to spin texture excitations and a Coulomb-like behavior at large B. From the global gap-reduction we get information about the mobility edges in the fractional quantum Hall regime.