Quantum-dot cellular automata: Line and majority logic gate

An introduction to the operation of quantum-dot cellular automata is presen ted, along with recent experimental results. Quantum-dot cellular automata (QCA) is a transistorless computation paradigm that addresses the issues of device density and interconnection. The basic building blocks of the QCA a rchitecture, such as AND, OR, and NOT are presented. The experimental devic es presented are QCA cells where the dots are metal islands, coupled by cap acitors and tunnel junctions. A line of three two-dot cells is presented, w hich demonstrates that there are no metastable states in a QCA line. The fi nal experiment presented is a QCA majority gate, a programmable AND/OR logi c gate.