Browse Prior Art Database

Quantum Switch

IP.com Disclosure Number: IPCOM000034838D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Chang, LL: AUTHOR [+3]

Abstract

A very fast electrical switch can be obtained by the drastic change in the two-terminal magnetoresistance of a high mobility 2D electron gas. At low temperatures, T & 4 K, the two-terminal resistance of a high-mobility 2D electron gas can be extremely high (R>/ML) at certain values of a magnetic field applied perpendicularly to the 2D gas. Figs. 1, 2 and 3 show the performance, the cross-sectional and top views of the device, respectively. The sharp rise in resistance occurs at critical fields for which the Fermi energy is between Landau levels (or spin-split Landau levels). This effect is employed to make a quantum-switch device. The device structure would be a GaAs-GaA1As modulation-doped heterostructure grown on a semi-insulating substrate, shown in Fig. 2.

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Quantum Switch

A very fast electrical switch can be obtained by the drastic change in the two- terminal magnetoresistance of a high mobility 2D electron gas. At low temperatures, T & 4 K, the two-terminal resistance of a high-mobility 2D electron gas can be extremely high (R>/ML) at certain values of a magnetic field applied perpendicularly to the 2D gas. Figs. 1, 2 and 3 show the performance, the cross- sectional and top views of the device, respectively. The sharp rise in resistance occurs at critical fields for which the Fermi energy is between Landau levels (or spin-split Landau levels). This effect is employed to make a quantum-switch device. The device structure would be a GaAs-GaA1As modulation-doped heterostructure grown on a semi-insulating substrate, shown in Fig. 2. Materials, such as GaSb-InAs-GaSb and InGaAs-InP, could serve the purpose. The epilayer is shaped into a long and narrow rectangular bar of 2 mm and a width of
0.1 mm and ohmic contacts are made to the 2D gas by evaporating and alloying Au-Ge at the two ends of the bar and covering its entire width, as shown in Fig.
3. The magnetic field is provided by either a superconducting solenoid or a Bitter coil.

(Image Omitted)

In operation, the device could be inserted in a small superconducting solenoid providing up to 20 kG. By varying the current intensity between the resonant or critical field and the off-resonant conditions, the resistance could be changed by an order of magnitude. Any of the...