Direct measurements of the fractional quantum Hall effect gaps

Khrapai, V. S.; Shashkin, A. A.; Trokina, M. G.; Dolgopolov, V. T.; Pellegrini, V.; Beltram, F.; Biasiol, G.; Sorba, L.

Direct measurements of the fractional quantum Hall effect gaps

Authors

Description

We measure the chemical potential jump across the fractional gap in the low-temperature limit in the two-dimensional electron system of GaAs/AlGaAs single heterojunctions. In the fully spin-polarized regime, the gap for filling factor nu=1/3 increases LINEARLY with magnetic field and is coincident with that for nu=2/3, reflecting the electron-hole symmetry in the spin-split Landau level. In low magnetic fields, at the ground-state spin transition for nu=2/3, a correlated behavior of the nu=1/3 and nu=2/3 gaps is observed.