Can atoms stage 'riots' against uniformity?
Washington | November 18, 2008 3:35:06 PM IST
Struck by laser light, electrons of crystal atoms begin moving back and forth rhythmically, like nanoscale soldiers on drill.
But according to a new theory developed by Johns Hopkins researchers, these very atoms can rebel against uniformity. Their electrons will begin moving apart and then joining together repeatedly like lively swing partners on a dance floor.
Moreover, the researchers said, this atomic freestyle dancing can be controlled, paving the way for tiny computer components that emit less heat and new sensors to detect bio-hazards and medical conditions.
"By choosing particular atoms in the proper configuration and directing the right laser light at them, we could control the behaviour of these 'nano-dancers,'" said Alexander E. Kaplan, a professor in computer engineering at Johns Hopkins. "The essential thing is, these are completely designable atomic structures."
The next step for researchers in his lab is to conduct lab experiments in an effort to validate the theory and predictions advanced by Kaplan and Sergei N. Volkov.
Kaplan, an internationally renowned nonlinear optics expert who studies how matter interacts with strong light, said his and Volkov's "nano-riot" idea runs counter to a widely accepted concept.
For decades, Kaplan said, scientists have adhered to the Lorentz-Lorenz theory, which asserts that the atomic electrons in a crystal, exposed to a laser beam, will move back and forth in tandem in a uniform way under any conditions.
"But we've concluded that under certain circumstances, the nearest atoms will behave much differently," he said. "Their electrons will move violently apart and come back together again, staging a sort of 'nano-riot.'"
Computer makers, trying to produce ever smaller metallic or semiconductor components, have run into problems related to the excessive release of heat, said a Johns Hopkins press release.
However, the nanoscale switch envisioned by Kaplan would be a dielectric, meaning it would involve no exchange of free electrons in the structure. Because of this, the proposed components would generate far less heat.
If their theory is confirmed, the Johns Hopkins researchers foresee other applications for these nanoscale atomic systems.
The tiny lattices, they say, could be designed so that when a specific foreign bio-molecule enters a system, the atomic electron 'dancing' would stop.
Because of this characteristic, they said, the system could be designed to trigger an alarm signal whenever a bio-hazard or perhaps a cancer cell was detected.
These findings have been described in Physical Review Letters.
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