title: Colossal magnetoresistance in an ultraclean weakly interacting 2D Fermi liquid.
abstract: We report the observation of a new phenomenon of colossal magnetoresistance in a 40 nm wide GaAs quantum well in the presence of an external magnetic field applied parallel to the high-mobility 2D electron layer. In a strong magnetic field, the magnetoresistance is observed to increase by a factor of ∼300 from 0 to 45 T without the system undergoing any metal-insulator transition. We discuss how this colossal magnetoresistance effect cannot be attributed to the spin degree of freedom or localization physics, but most likely emanates from strong magneto-orbital coupling between the two-dimensional electron gas and the magnetic field. Our observation is consistent with a field-induced 2D-to-3D transition in the confined electronic system.
authors.affiliation: Department of Physics, McGill University, Montreal, H3A 2T8, Canada.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Zhou
authors.forename: B A
authors.initials: BA
authors.lastname: Piot
authors.forename: M
authors.initials: M
authors.lastname: Bonin
authors.forename: L W
authors.initials: LW
authors.lastname: Engel
authors.forename: S
authors.initials: S
authors.lastname: Das Sarma
authors.forename: G
authors.initials: G
authors.lastname: Gervais
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: West