title: Disorder-Induced Stabilization of the Quantum Hall Ferromagnet.
abstract: We report on an absolute measurement of the electronic spin polarization of the ν=1 integer quantum Hall state. The spin polarization is extracted in the vicinity of ν=1 (including at exactly ν=1) via resistive NMR experiments performed at different magnetic fields (electron densities) and Zeeman energy configurations. At the lowest magnetic fields, the polarization is found to be complete in a narrow region around ν=1. Increasing the magnetic field (electron density) induces a significant depolarization of the system, which we attribute to a transition between the quantum Hall ferromagnet and the Skyrmion glass phase theoretically expected as the ratio between Coulomb interactions and disorder is increased. These observations account for the fragility of the polarization previously observed in high mobility 2D electron gas and experimentally demonstrate the existence of an optimal amount of disorder to stabilize the ferromagnetic state.
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS-UGA-UPS-INSA-EMFL, F-38042 Grenoble, France.
authors.forename: B A
authors.initials: BA
authors.lastname: Piot
authors.affiliation: Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, F-34095 Montpellier, France.
authors.forename: W
authors.initials: W
authors.lastname: Desrat
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS-UGA-UPS-INSA-EMFL, F-31400 Toulouse, France.
authors.forename: D K
authors.initials: DK
authors.lastname: Maude
authors.affiliation: CNRS, Laboratoire de Photonique et de Nanostructures (LPN), 91460 Marcoussis, France.
authors.forename: D
authors.initials: D
authors.lastname: Kazazis
authors.affiliation: CNRS, Laboratoire de Photonique et de Nanostructures (LPN), 91460 Marcoussis, France.
authors.forename: A
authors.initials: A
authors.lastname: Cavanna
authors.affiliation: CNRS, Laboratoire de Photonique et de Nanostructures (LPN), 91460 Marcoussis, France.
authors.forename: U
authors.initials: U
authors.lastname: Gennser