Journal article

Spin-excitations of the quantum Hall ferromagnet of composite fermions

  • Doretto, Ricardo L. Departamento de Física da Matéria Condensada, Instituto de Física "Gleb Wataghin," Universidade Estadual de Campinas, Brazil - Département de Physique, Université de Fribourg, Switzerland
  • Goerbig, Mark O. Département de Physique, Université de Fribourg, Switzerland - Laboratoire de Physique Théorique et de Hautes Énergies, CNRS UMR 7589, Universités Paris 6 et 7, 4, France
  • Lederer, P. Laboratoire de Physique des Solides, Bât. 510 (associé au CNRS), Université Paris-Sud, France
  • Caldeira, A. O. Departamento de Física da Matéria Condensada, Instituto de Física "Gleb Wataghin," Universidade Estadual de Campinas, Brazil
  • Morais Smith, Cristiane de Département de Physique, Université de Fribourg, Switzerland - Institute for Theoretical Physics, University of Utrecht, The Netherlands
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    19.07.2005
Published in:
  • Physical Review B. - 2005, vol. 72, no. 035341
English The spin excitations of a fractional quantum Hall system are evaluated within a bosonization approach. In a first step, we generalize Murthy and Shankar's Hamiltonian theory of the fractional quantum Hall effect to the case of composite fermions with an extra discrete degree of freedom. Here, we mainly investigate the spin degrees of freedom, but the proposed formalism may be useful also in the study of bilayer quantum-Hall systems, where the layer index may formally be treated as an isospin. In a second step, we apply a bosonization scheme, recently developed for the study of the two-dimensional electron gas, to the interacting composite-fermion Hamiltonian. The dispersion of the bosons, which represent quasiparticle-quasihole excitations, is analytically evaluated for fractional quantum Hall systems at ν=1/3 and ν=1/5. The finite width of the two-dimensional electron gas is also taken into account explicitly. Furthermore, we consider the interacting bosonic model and calculate the lowest-energy state for two bosons. In addition to a continuum describing scattering states, we find a bound-state of two bosons. This state is interpreted as a pair excitation, which consists of a skyrmion of composite fermions and an antiskyrmion of composite fermions. The dispersion relation of the two-boson state is evaluated for ν=1/3 and ν=1/5. Finally, we show that our theory provides the microscopic basis for a phenomenological nonlinear σ model for studying the skyrmion of composite fermions.
Faculty
Faculté des sciences
Department
Physique
Language
  • English
Classification
Physics
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/300033
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