TY - JOUR
T1 - Magnetism and pseudo-magnetism in quantum Hall systems
AU - De Poortere, E. P.
AU - Tutuc, E.
AU - Pillarisetty, R.
AU - Melinte, S.
AU - Shayegan, M.
N1 - Funding Information:
This work was supported by DOE and NSF grants. We acknowledge fruitful discussions with Ravin Bhatt, Duncan Haldane, and Allan MacDonald, and thank Eric Palm and Tim Murphy for their technical assistance. Part of this work was performed at the National High Magnetic Field Laboratory in Tallahassee, FL, which is also supported by the NSF.
PY - 2003/12
Y1 - 2003/12
N2 - We present the latest results of our transport measurements, in the quantum Hall (QH) regime, in two different systems: AlAs two-dimensional (2D) electrons, and GaAs bilayer 2D hole systems. The magneto-resistance of AlAs 2D electrons exhibits sharp, hysteretic spikes at the crossings of the Landau levels with opposite spin. The spikes signal collective magnetic transitions between the two Ising-like states of the QH ferromagnet at the level crossings. We report a critical behavior in the temperature dependence of the spikes' width and amplitude, from which we deduce the Curie temperature of the QH ferromagnet. In GaAs bilayer hole systems, when the two layers have unequal densities, we observe a hysteretic magneto-resistance when one of the layers is near ν=1 filling factor. The resistance in the hysteretic field range shows an unusual time dependence, consisting of abrupt jumps and slow relaxations. The data signals an instability in the charge distribution of the two layers.
AB - We present the latest results of our transport measurements, in the quantum Hall (QH) regime, in two different systems: AlAs two-dimensional (2D) electrons, and GaAs bilayer 2D hole systems. The magneto-resistance of AlAs 2D electrons exhibits sharp, hysteretic spikes at the crossings of the Landau levels with opposite spin. The spikes signal collective magnetic transitions between the two Ising-like states of the QH ferromagnet at the level crossings. We report a critical behavior in the temperature dependence of the spikes' width and amplitude, from which we deduce the Curie temperature of the QH ferromagnet. In GaAs bilayer hole systems, when the two layers have unequal densities, we observe a hysteretic magneto-resistance when one of the layers is near ν=1 filling factor. The resistance in the hysteretic field range shows an unusual time dependence, consisting of abrupt jumps and slow relaxations. The data signals an instability in the charge distribution of the two layers.
KW - Aluminum arsenide
KW - Hysteresis
KW - Quantum Hall ferromagnets
KW - Two-dimensional bilayer
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U2 - 10.1016/j.physe.2003.09.029
DO - 10.1016/j.physe.2003.09.029
M3 - Conference article
AN - SCOPUS:0344495381
VL - 20
SP - 123
EP - 132
JO - Physica E: Low-Dimensional Systems and Nanostructures
JF - Physica E: Low-Dimensional Systems and Nanostructures
SN - 1386-9477
IS - 1-2
T2 - Proceedings of the International Symposium at Quantum Hall Effect
Y2 - 2 July 2003 through 5 July 2003
ER -