Quantum Hall Stripes in High-Density GaAs/AlGaAs Quantum Wells

We report on quantum Hall stripes (QHSs) formed in higher Landau levels of GaAs/AlGaAs quantum wells with high carrier density (n(e) > 4 x 10(11) cm(-2)) which is expected to favor QHS orientation along the unconventional < 1 (1) over bar0 > crystal axis and along the in-plane magnetic field B-parallel to. Surprisingly, we find that at B-parallel to = 0 QHSs in our samples are aligned along the < 110 > direction and can be reoriented only perpendicular to B-parallel to. These findings suggest that high density alone is not a decisive factor for either abnormal native QHS orientation or alignment with respect to B-parallel to, while quantum confinement of the 2DEG likely plays an important role.