'Quantum mirage' may replace wires in nanocircuits, say IBM scientists
Semiconductor Business News
(02/03/00, 12:48:17 PM EDT)
SAN JOSE--Scientists here at IBM Corp. today reported the discovery of a method to transport information on the atomic scale using the wave nature of electrons instead of wiring. The phenomenon, called "quantum mirage," might enable data transfer in atom-scale integrated circuits without the use of conventional interconnects, suggested IBM.
"This is a fundamentally new way of guiding information through a solid," said Donald M. Eigler, an IBM Fellow who is the lead researcher on the project at the Almaden Research Center in San Jose. "We call it a 'mirage' because we project information about one atom to another spot where there is no atom."
As solid-state devices shrink toward atomic dimensions, the behavior of electrons will change from being like particles to being like waves, noted IBM researchers. The quantum mechanics of electrons at this scale will make it difficult to use tiny wiring as chip interconnects.
IBM scientists created the quantum mirage technique using a low-temperature scanning tunneling microscope (STM). The operation of quantum mirage was described as being similar to light waves focused on a single spot by optical lenses and mirrors, or sound being moved inside buildings by "whisper spots," as is the case in the Old House of Representatives Chamber in the U.S. Capitol Building.
Significant improvements in quantum mirage are still needed before this method becomes useful in actual circuits, Donald said. "Making each ellipse with the STM is currently impractically slow," he said. "They would have to be easily and rapidly produced, connections to other components would also have to be devised and a rapid and power-efficient way to modulate the available quantum states would need to be developed."
The IBM scientists said they have built and tested elliptical corrals up to 20 nanometers long with the width as little as half that. The electron density and intensity of the mirage depends on the quantum state, not the distance between the foci. The researchers reported the discovery of quantum mirage in the Feb. 3 issue of Nature, an international scientific journal published in London.
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