SINGLE-ELECTRON CHARGING IN PARALLEL COUPLED QUANTUM DOTS

We report low-temperature conductance measurements in the Coulomb bloc kade regime on two nominally identical tunnel-coupled quantum dots in parallel defined electrostatically in the two-dimensional electron gas of a GaAs/AlGaAs heterostructure. At low interdot tunnel coupling we find that the conductance measured through one dot is sensitive to the charge state of the neighboring dot. At larger interdot coupling the conductance data reflect the role of quantum charge fluctuations betwe en the dots. As the interdot conductance approaches 2e(2)/h, the coupl ed dots behave as a single large dot. (C) 1996 Academic Press Limited