3 research outputs found
Direct measurements of the fractional quantum Hall effect gaps
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
Filling factor dependence of the fractional quantum Hall effect gap
We directly measure the chemical potential jump in the low-temperature limit
when the filling factor traverses the nu = 1/3 and nu = 2/5 fractional gaps in
two-dimensional (2D) electron system in GaAs/AlGaAs single heterojunctions. In
high magnetic fields B, both gaps are linear functions of B with slopes
proportional to the inverse fraction denominator, 1/q. The fractional gaps
close partially when the Fermi level lies outside. An empirical analysis
indicates that the chemical potential jump for an IDEAL 2D electron system, in
the highest accessible magnetic fields, is proportional to q^{-1}B^{1/2}