Experimental demonstration of clocked single-electron switching in quantum-dot cellular automata

A device representing a basic building block for clocked quantum-dot cellul ar automata architecture is reported. Our device consists of three floating micron-size metal islands connected in series by two small tunnel junction s where the location of an excess electron is defined by electrostatic pote ntials on gates capacitively coupled to the islands. In this configuration, the middle dot acts as an adjustable Coulomb barrier allowing clocked cont rol of the charge state of the device. Charging diagrams of the device show the existence of several operational modes, in good agreement with theory. The clocked switching of a single electron is experimentally demonstrated and advantages of this architecture are discussed. (C) 2000 American Instit ute of Physics. [S0003-6951(00)03428-8].