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.
Bishop
N C
NC
Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Padmanabhan
M
M
Vakili
K
K
Shkolnikov
Y P
YP
De Poortere
E P
EP
Shayegan
M
M