Investigation of an open quantum dot using a Coulombblockade quantum dot detector in a bilayer electron system

摘要

A system comprising of a closed quantum dot in the upper layer of a GaAs-AlxGa1_ xAs bilayer electron system coupled electrostatically to an open quantum dot in thelower layer was investigated as a back gate voltage was swept. Simultaneous independentmeasurements of the conductances of the two layers were performed at temperatures less than50mK. Coulomb blockade conductance oscillations in the upper quantum dot were used tomeasure changes in the electrostatic screening properties of the lower open quantum dot. Thisscreening depended both on the geometry and the quantum mechanics of the open dot. Theexperimental results were compared to a three dimensional model based on the band structureand electrostatics of the semiconductor heterostructure.