There are provided a
point contact array, in which a plurality of point contacts are arranged, each
point contact electrically and reversibly controlling conductance between electrodes and being applicable to an arithmetic circuit, a logic circuit, and a memory device, a NOT circuit, and an
electronic circuit using the same. A circuit includes a plurality of point contacts each composed of a first
electrode made of a compound conductive material having
ionic conductivity and
electronic conductivity and a second
electrode made of a conductive substance. The conductance of each
point contact is controlled to realize the circuit. Ag2S, Ag2Se, Cu2S, or Cu2Se is preferably used as the compound conductive material. When a
semiconductor or insulator material is interposed between the electrodes, a
crystal or an amorphous material of GeSx, GeSex, GeTex, or WOx (0<x<100) is preferably used as the
semiconductor or insulator material. A NOT circuit is realized using a device which includes an atomic switch serving as a two-terminal device, the device including a first
electrode made of a compound conductive material having
ionic conductivity and
electronic conductivity and a second electrode made of a conductive substance, and capable of controlling conductance between the electrodes.