title: Two-stage Kondo effect in a quantum dot at a high magnetic field.
abstract: We report a strong Kondo effect (Kondo temperature approximately 4 K) at high magnetic field in a selective area growth semiconductor quantum dot. The Kondo effect is ascribed to a singlet-triplet transition in the ground state of the dot. At the transition, the low-temperature conductance approaches the unitary limit. Away from the transition, for low bias voltages and temperatures, the conductance is sharply reduced. The observed behavior is compared to predictions for a two-stage Kondo effect in quantum dots coupled to single-channel leads.
authors.affiliation: Department of Applied Physics, DIMES, and ERATO Mesoscopic Correlation Project, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands.
authors.forename: W G
authors.initials: WG
authors.lastname: van der Wiel
authors.forename: S
authors.initials: S
authors.lastname: De Franceschi
authors.forename: J M
authors.initials: JM
authors.lastname: Elzerman
authors.forename: S
authors.initials: S
authors.lastname: Tarucha
authors.forename: L P
authors.initials: LP
authors.lastname: Kouwenhoven
authors.forename: J
authors.initials: J
authors.lastname: Motohisa
authors.forename: F
authors.initials: F
authors.lastname: Nakajima
authors.forename: T
authors.initials: T
authors.lastname: Fukui