STOCHASTIC COULOMB-BLOCKADE AND SCALING OF CHARGING ENERGY IN A DOUBLE-QUANTUM DOT SYSTEM

We have studied the transport properties of a device consisting of two quantum dots, defined electrostatically in a (Al,Ga)As heterostructur e. In the series conductance of the two dots, we observe irregularly s paced conductance peaks of fluctuating amplitude. This behaviour resul ts from transport in the stochastic Coulomb blockade regime. In a seco nd experiment, we measure the charging energy of one dot through the e ffect of its potential (which varies in a saw-tooth fashion with gate voltage) on the conductance of the other dot. We find that the chargin g energy scales quadratically with the reflection probability of the t unnel barriers, in agreement with a recent theory.