title: Electrical control of interdot electron tunneling in a double InGaAs quantum-dot nanostructure.
abstract: We employ ultrafast pump-probe spectroscopy to directly monitor electron tunneling between discrete orbital states in a pair of spatially separated quantum dots. Immediately after excitation, several peaks are observed in the pump-probe spectrum due to Coulomb interactions between the photogenerated charge carriers. By tuning the relative energy of the orbital states in the two dots and monitoring the temporal evolution of the pump-probe spectra the electron and hole tunneling times are separately measured and resonant tunneling between the two dots is shown to be mediated both by elastic and inelastic processes. Ultrafast (<5  ps) interdot tunneling is shown to occur over a surprisingly wide bandwidth, up to ∼8  meV, reflecting the spectrum of exciton-acoustic phonon coupling in the system.
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Müller
authors.forename: A
authors.initials: A
authors.lastname: Bechtold
authors.forename: C
authors.initials: C
authors.lastname: Ruppert
authors.forename: M
authors.initials: M
authors.lastname: Zecherle
authors.forename: G
authors.initials: G
authors.lastname: Reithmaier
authors.forename: M
authors.initials: M
authors.lastname: Bichler
authors.forename: H J
authors.initials: HJ
authors.lastname: Krenner
authors.forename: G
authors.initials: G
authors.lastname: Abstreiter
authors.forename: A W
authors.initials: AW
authors.lastname: Holleitner
authors.forename: J M
authors.initials: JM
authors.lastname: Villas-Boas
authors.forename: M
authors.initials: M
authors.lastname: Betz
authors.forename: J J
authors.initials: JJ
authors.lastname: Finley