Feb. 14, 2000 A new thermoelectric material that may someday double the speed at which a computer operates has been discovered by a team of scientists, including several from Michigan State University.
When jolted with an electrical current, the temperature of current thermoelectric materials can drop by as much as 60 degrees. This new material could make the drop as great as 100 degrees. Eventually it could be used to cool items such as computer chips, which operate much more efficiently at lower temperatures.
The discovery of this material, which is a combination of three elements - cesium, bismuth and tellurium - is detailed in the Feb. 11 issue of the journal Science.
"We are excited about this material because it out-performs the current material at this lower temperature," said Mercouri Kanatzidis, an MSU professor of chemistry in whose laboratory the discovery was made. "The material currently used in this process was discovered in the 1950s and since then no one has been able to do better.
"What we've done, at least so far, is demonstrate that a new material actually exists and can out-perform the current material in a given temperature range."
Another problem this material could eventually help to alleviate is the relatively inefficient way computers cool themselves. Currently, most computers use fans for this extremely important process.
"As these computer chips become smaller and more powerful, they generate more heat," Kanatzidis said. "A fan is not going to be enough. We'll need a more active way to remove the heat."
It's not impossible to cool electronic devices to very low temperatures, but it's challenging. For example, liquid helium and liquid nitrogen work well, but not necessarily on a home computer.
"Those involve additional infrastructure that makes it bulky and inconvenient," Kanatzidis said. "People would like to have an electronic device they can plug in and cool to lower temperatures."
Kanatzidis stresses that much additional work is needed before this new material will have practical applications.
"Other, more practical issues, need to be explored," he said. "What is its long-term stability? Can it be manufactured in large quantities? Can it be further improved? Will it be affordable?"
Thermoelectric materials also can work in reverse, Kanatzidis said. When a current flows through it, one end is cooled while the other is heated.
"In situations like that, that waste heat could possibly be converted into useful electricity," he said.
The discovery of the new material by Kanatzidis and colleagues stems from several years of basic research. Must of the research was funded by a grant from the Office of Naval Research.
Other members of the research team include Duck-Young Chung, an MSU research associate; Tim Hogan, MSU professor of electrical engineering; Ctirad Uher and Marina Bastea of the University of Michigan; and Carl Kannawurf, Paul Brazis and Melissa Rocci-Lane of Northwestern University.
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