paper

Interlayer Exchange Interactions, SU(4) Soft Waves and Skyrmions in Bilayer Quantum Hall Ferromagnets

arXiv:cond-mat/0104448 · doi:10.1103/PhysRevB.65.075311

Abstract

The Coulomb exchange interaction is the driving force for quantum coherence in quantum Hall systems. We construct a microscopic Landau-site Hamiltonian for the exchange interaction in bilayer quantum Hall ferromagnets, which is characterized by the SU(4) isospin structure. By taking a continuous limit, the Hamiltonian gives rise to the SU(4) nonlinear sigma model in the von-Neumann-lattice formulation. The ground-state energy is evaluated at filling factors . It is shown at that there are 3 independent soft waves, where only one soft wave is responsible for the coherent tunneling of electrons between the two layers. It is also shown at that there are 3 independent skyrmion states apart from the translational degree of freedom. They are CP skyrmions enjoying the spin-charge entanglement confined within the \LLL.

12 pages, 2 figures

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