dc.contributor.author Kramer, B dc.contributor.author Magnoli, N dc.contributor.author Mariani, E dc.contributor.author Merlo, M dc.contributor.author Napoli, F dc.contributor.author Sassetti, M dc.date.accessioned 2016-03-10T16:59:57Z dc.date.issued 2003 dc.description.abstract The model of Composite Fermions for describing interacting electrons in two dimensions in the presence of a magnetic field is described. In this model, charged Fermions are combined with an even number of magnetic flux quanta in such a way that the external magnetic field is compensated on the average for half filling of Landau levels and the interaction is incorporated into an effective mass of the new composite particles. The fluctuations of the Chern-Simons gauge field, which describes formally the flux attachment, induce new interactions between the Composite Fermions. The effective interaction is investigated with particular emphasis on the role of the electron spin at filling factor $\nu=1/2$. For a system with equal numbers of spin-up and spin-down electrons it is found that the dominant effective interaction is attractive in the spin-singlet channel. This can induce a ground state consisting of Cooper pairs of Composite Fermions that is separated from the excited states by a gap. The results are used to understand recent spin polarization measurements done in the region of the Fractional Quantum Hall Effect at different constant filling factors. en_GB dc.description.sponsorship Acknowledgment This work has been supported by the European Union via the TMR en_GB and RTN programmes (FMRX-CT98-0180, HPRN-CT2000-00144), by the Deutsche Forschungsgemeinschaft within the Schwerpunkt “Quanten-Hall-Effekt” of the Universit¨at Hamburg, and by the Italian MURST via PRIN00. dc.identifier.citation B. Kramer, E. Mariani, N. Magnoli, M. Merlo, F. Napoli, M. Sassetti, (2003) in Composite Fermions with spin at ν = 1/2, pp. 395-415 in Proceedings of the International School of Physics "Enrico Fermi"; Volume 151: Quantum Phenomena in Mesoscopic Systems. en_GB dc.identifier.doi 10.3254/978-1-61499-007-9-395 dc.identifier.uri http://hdl.handle.net/10871/20659 dc.language.iso en en_GB dc.publisher IOS Press en_GB dc.relation.url http://arxiv.org/abs/cond-mat/0212423v1 en_GB dc.rights © Societa Italiana di Fisica en_GB dc.subject cond-mat.mes-hall en_GB dc.subject cond-mat.mes-hall en_GB dc.subject cond-mat.str-el en_GB dc.title Composite Fermions with Spin at $ν=1/2$ en_GB dc.type Conference paper en_GB dc.date.available 2016-03-10T16:59:57Z dc.identifier.isbn 978-1-58603-384-2 dc.identifier.issn 0074-784X dc.description to be published in proceedings of Varenna Summer School "E. Fermi": Course CLI "Quantum phenomena in mesoscopic systems", July 2002 en_GB dc.description This is the author accepted manuscript. The final version is available from IOS press via the DOI in this record. en_GB dc.identifier.journal Proceedings- International School of Physics Enrico Fermi en_GB
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