Regensburg 2004 – scientific programme
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HL: Halbleiterphysik
HL 22: Transport im hohen Magnetfeld/Quanten-Hall-Effekt
HL 22.6: Talk
Tuesday, March 9, 2004, 16:30–16:45, H14
On ground states of interacting Composite Fermions with spin at half filling — •Matteo Merlo1, Nicodemo Magnoli2, Maura Sassetti1, and Bernhard Kramer3 — 1Dipartimento di Fisica, INFM-LAMIA, Università di Genova, Via Dodecaneso 33, I-16146 Genova, Italy — 2Dipartimento di Fisica, INFN, Università di Genova, Via Dodecaneso 33, I-16146 Genova, Italy — 3I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, D-20355 Hamburg, Germany
The effects of interactions in a 2D electron system in a strong magnetic field at the coincidence of two Landau levels with opposite spins and at filling factors 1/2 are studied. Via the Chern-Simons gauge transformation, the system is mapped to Composite Fermions. The fluctuations of the gauge field induce an effective interaction between the Composite Fermions which can be attractive in both the particle-particle [1,2] and in the particle-hole channel. As a consequence, spin-zero ground states of Composite Fermion particle-particle or particle-hole pairs can exist. The competition between the two possible ground states is discussed and the results are compared with experiments.
[1] E. Mariani, N. Magnoli, F. Napoli, M. Sassetti, and B. Kramer, Phys. Rev. B 66, 241303 (2002) .
[2] B. Kramer, N. Magnoli, E. Mariani, M. Merlo, F. Napoli, and M. Sassetti, in Quantum Phenomena in Mesoscopics Physics, Proceedings of the International School of Physics Enrico Fermi, Varenna, 2002.