title: Separation of neutral and charge modes in one-dimensional chiral edge channels.
abstract: Coulomb interactions have a major role in one-dimensional electronic transport. They modify the nature of the elementary excitations from Landau quasiparticles in higher dimensions to collective excitations in one dimension. Here we report the direct observation of the collective neutral and charge modes of the two chiral co-propagating edge channels of opposite spins of the quantum Hall effect at filling factor 2. Generating a charge density wave at frequency f in the outer channel, we measure the current induced by inter-channel Coulomb interaction in the inner channel after a 3-μm propagation length. Varying the driving frequency from 0.7 to 11 GHz, we observe damped oscillations in the induced current that result from the phase shift between the fast charge and slow neutral eigenmodes. We measure the dispersion relation and dissipation of the neutral mode from which we deduce quantitative information on the interaction range and parameters.
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR8551), Université Pierre et Marie Curie, Université Paris Diderot 24 rue Lhomond, Cedex 05, Paris 75231, France.
authors.forename: E
authors.initials: E
authors.lastname: Bocquillon
authors.forename: V
authors.initials: V
authors.lastname: Freulon
authors.forename: J-M
authors.initials: JM
authors.lastname: Berroir
authors.forename: P
authors.initials: P
authors.lastname: Degiovanni
authors.forename: B
authors.initials: B
authors.lastname: Plaçais
authors.forename: A
authors.initials: A
authors.lastname: Cavanna
authors.forename: Y
authors.initials: Y
authors.lastname: Jin
authors.forename: G
authors.initials: G
authors.lastname: Fève