title: Transmission phase of a singly occupied quantum dot in the Kondo regime.
abstract: We report on the phase measurements on a quantum dot containing a single electron in the Kondo regime. Transport takes place through a single orbital state. Although the conductance is far from the unitary limit, we measure directly, for the first time, a transmission phase as theoretically predicted of pi/2. As the dot's coupling to the leads is decreased, with the dot entering the Coulomb blockade regime, the phase reaches a value of pi. Temperature shows little effect on the phase behavior in the range 30-600 mK, even though both the two-terminal conductance and amplitude of the Aharonov-Bohm oscillations are strongly affected. These results also suggest that previous phase measurements involved transport through more than a single level.
authors.affiliation: Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Zaffalon
authors.forename: Aveek
authors.initials: A
authors.lastname: Bid
authors.forename: M
authors.initials: M
authors.lastname: Heiblum
authors.forename: D
authors.initials: D
authors.lastname: Mahalu
authors.forename: V
authors.initials: V
authors.lastname: Umansky