Session Y37 - Quantum Dots: Transport.
ORAL session, Friday morning, March 26
520D, Palais des Congres
Direct observation of single electron tunneling (SET) through a potential barrier requires embedding the barrier in a high-impedance electromagnetic environment. To this end, we have fabricated staggered arrays of quantum point contacts (QPCs) across a narrow conducting channel in a GaAs/AlGaAs heterostructure containing a two-dimensional electron gas. The conductance G versus gate voltage of such an array of 10 QPCs shows plateau-like structures at fractions of the conductance quantum, G_0=2e^2/h. The last plateau occurs at G\approx0.15G_0, beyond which G drops sharply to zero, suggesting this plateau corresponds to one open channel in each QPC. Placing a tunnel barrier between a pair of such arrays embeds it in a high-impedance environment at the frequencies relevant to SET. We will present further measurements on the nanostructure, made using an integrated radio frequency single electron transistor placed close to the tunnel barrier.