title: SU(3) and SU(4) Singlet Quantum Hall States at ν=2/3.
abstract: We report on an exact diagonalization study of fractional quantum Hall states at a filling factor of ν=2/3 in a system with a fourfold degenerate n=0 Landau level and SU(4) symmetric Coulomb interactions. Our investigation reveals previously unidentified SU(3) and SU(4) singlet ground states which appear at a flux quantum shift 2 when a spherical geometry is employed and lie outside the established composite-fermion or multicomponent Halperin state patterns. We evaluate the two-particle correlation functions of these states and discuss quantum phase transitions in graphene between singlet states with a different number of components as the magnetic field strength is increased.
authors.affiliation: Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Fengcheng
authors.initials: F
authors.lastname: Wu
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Inti
authors.initials: I
authors.lastname: Sodemann
authors.affiliation: Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Allan H
authors.initials: AH
authors.lastname: MacDonald
authors.affiliation: Laboratoire de Physique Théorique et Modèles statistiques, CNRS and Université Paris-Sud, Orsay 91405, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Jolicoeur