Quantum-dot cellular automata: computing with coupled quantum dots.

We discuss novel nanoelectronic architecture paradigms based on cells composed of coupled quantum-dots. Boolean logic functions may be implemented in specific arrays of cells representing binary information, the so-called quantum-dot cellular automata (QCA). Cells may also be viewed as carrying analogue information and we outline a network-theoretic description of such quantum-dot nonlinear networks (Q-CNN). In addition, we discuss possible realizations of these structures in a variety of semiconductor systems (including GaAs/AlGaAs, Si/SiGe, and Si/SiO2), rings of metallic tunnel junctions, and candidates for molecular implementations. We report the experimental demonstration of all the necessary elements of a QCA cell, including direct measurement of the charge polarization of a double-dot system, and direct control of the polarization of those dots via single electron transitions in driver dots. Our experiments are the first demonstration of a single electron controlled by single electrons. [ABSTRACT FROM AUTHOR]