Valley polarization and susceptibility of composite fermions around a filling factor nu=3/2.
We report magnetotransport measurements of fractional quantum Hall states in an AlAs quantum well around a Landau level filling factor nu=3/2, demonstrating that the quasiparticles are composite fermions (CFs) with a valley degree of freedom. By monitoring the valley level crossings for these states as a function of applied symmetry-breaking strain, we determine the CF valley susceptibility and polarization. The data can be explained well by a simple Landau level fan diagram for CFs, and are in nearly quantitative agreement with the results reported for CF spin polarization.
Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
N C
NC
Bishop
M
M
Padmanabhan
K
K
Vakili
Y P
YP
Shkolnikov
E P
EP
De Poortere
M
M
Shayegan