Hitachi, Ltd.

Shiroo Kamohara

Kozo Katayama

Sigeo Ihara

Toru Toyabe

Shuichi Yamamoto

Hitoshi Matsuo

Peter M Lee

A logical operation circuit in which wiring as generally performed between transistors is made unnecessary to improve reliability, stability and integration degree of a logical circuit using a tunnel phenomenon, for example, a single-electron tunnel phenomenon, or a flight phenomenon of a particle group. Conducting materials are arranged in a two-dimensional plane or three-dimensional space in the logical circuit. When two conducting materials are arranged to be nearest each other, the two conducting materials are connected, for example, by a single-electron tunnel phenomenon. When two conducting materials are arranged to be not nearest, there is no connection between the conducting materials by the tunnel phenomenon. Propagation of electrons is controlled by changing the arrangement. Further, because particles which have entered input regions move toward different flight directions respectively from a branch region on the basis of the property that two particles cannot enter simultaneously within an effective scatter distance by repulsive interaction between particles, flight of particles is controlled so as to enter or not branched particles into an observation region to thereby construct a wiringless logical operation circuit.

Wiringless logical operation circuits

An interband single-electron tunnel/transistor utilizes an interband single-electron tunneling phenomenon between a valence band and a conduction band through a p-n junction. The transistor includes the combination of microcapacities as fundamental constituent elements each formed by joining a p-type semiconductor material doped with an impurity in the degree of concentration with which a Fermi level overlaps a valence band and an n-type semiconductor material doped with an impurity in the degree of concentration with which the Fermi level overlaps a conduction band. The microcapacity includes a p-n junction having a junction area with which interband electron tunneling is inhibited due to Coulomb blockade.

Interband single-electron tunnel transistor and integrated circuit

A quantum memory device in which a memory operation is enabled even if the structure of a Josephson device is reduced in size. Each memory cell of the quantum memory device includes a superconducting quantum interference device having two Josephson junctions, a write word line for supplying a current to the superconducting quantum interference device, a write data line and a magnetic field detection line magnetically coupled with the superconducting quantum interference device, a three-terminal switching device for turning a signal of the magnetic field detection line on and off to transfer the signal to a read data line, and a read word line connected to a gate of the three-terminal switching device. The junction area of the Josephson junction is made small to oscillate a magnetic flux so that information is stored in accordance with the phase of oscillation of the magnetic flux. An induced current produced by an oscillating flux of a dummy cell and an induced current produced by an oscillating flux of each memory cell are compared to detect the phases of flux oscillation of the dummy and memory cells, thereby reading information.

Quantum memory device

An interband single-electron tunnel transistor utilizes an interband single-electron tunneling phenomenon between a valence band and a conduction band through a p-n junction. The transistor includes the combination of microcapacities as fundamental constituent elements each formed by joining a p-type semiconductor material doped with an impurity in the degree of concentration with which a Fermi level overlaps a valence band and an n-type semiconductor material doped with an impurity in the degree of concentration with which the Fermi level overlaps a conduction band. The microcapacity includes a p-n junction having a junction area with which interband electron tunneling is inhibited due to Coulomb blockade.

Growing community of inventors

Kokubunji, Japan

Shiroo Kamohara