BISTABLE SATURATION DUE TO SINGLE-ELECTRON CHARGING IN RINGS OF TUNNEL-JUNCTIONS

The behavior of rings of four small-capacitance tunnel junctions that are charged with two extra electrons is examined. Single electron charging effects result in quantization of charge on the metal electrode islands. To minimize the total electrostatic energy, the electrons localize on opposite electrodes, leading to a charge alignment in one of two configurations. We consider such rings as cells that may be capacitively coupled to each other in a cellular automaton architecture. The interaction between cells results in strong bistable saturation in the cell's charge alignment which may be used to encode binary information. Lines of such cells can be viewed as binary wires.