San Jose, CA -Physicists at IBM's Almaden Research Center have demonstrated a working circuit as small as an atom-that's one-tenth of a nanometer wide-which does not use conventional wiring. The breakthrough promises to radically change modern electronics, making for new circuits with a thousand times the storage capacity of today's chips.
The atomic-sized circuit employs the wave nature of electrons to transfer data through a solid in place of wires in a "quantum mirage effect."
"We call it a mirage because we project information about one atom to another spot where there is no atom," said Donald M. Eigler, lead project researcher.
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When a single atom (purple peak) in this elliptical ring is placed at one of the two focus points, some of its properties are transmitted (the purple spot). This may lead to an efficient way of moving information in future atomic-scale circuits.
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As computer circuits shrink to the atomic level, the behavior of electrons changes from being particle-like to wave-like. On such small scales, tiny wires don't conduct electrons as well as classical physics predicts. So quantum analogs must be available if nanocircuits are to achieve the performance advantages from their small size.
To create the quantum mirage, scientists moved several dozen cobalt atoms on a copper surface into an elliptical shaped ring-"quantum corral"-reflecting the copper's surface electrons within the ring into a wave pattern predicted by quantum mechanics.
The size and shape of the elliptical corral determine its quantum states-the energy and spatial distribution of the confined electrons. The IBM researchers used a quantum state that concentrated large electron densities at each focus point of the elliptical corral. When the scientists placed an atom of magnetic cobalt at one focus, a mirage appeared at the other focus: the same electronic states in the surface electrons surrounding the cobalt atom were detected even though no magnetic atom was actually there. The intensity of the mirage is about one-third of the intensity around the cobalt atom.
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