Magnetism and pseudo-magnetism in quantum Hall systems

E. P. De Poortere, E. Tutuc, R. Pillarisetty, S. Melinte, M. Shayegan

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)123-132
Number of pages10
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Issue number1-2
StatePublished - Dec 2003
EventProceedings of the International Symposium at Quantum Hall Effect - Stuttgart, Germany
Duration: Jul 2 2003Jul 5 2003

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


  • Aluminum arsenide
  • Hysteresis
  • Quantum Hall ferromagnets
  • Two-dimensional bilayer


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