Dr. Takeshi Egami:
ORNL Division of Metals and Ceramics;
Department of Materials Science and Engineering;
Department of Physics and Astronomy
Takeshi Egami, a recent addition to the joint UT-ORNL Distinguished Scientist family, likes his research to fly in the face of accepted ideas or rules.
If it doesn't, he's not interested.
"I always want to do something different; to be able to influence a field."
So while the creation of reactive, working, nano-sized particles is often dramatic, the discoveries alone don't hold Egami's attention.
"The chemists who create the molecules often don’t know why they work," he says.
Egami's job is to find out and to think about improving them.
An applied physicist, Egami gathers information about unusual local atomic arrangements to determine how atoms manage to control material properties.
His preference for the untried led him to successfully champion a technique called the atomic pair-density function, or PDF, a method used previously on glasses and liquids but rarely, if at all, to study local atomic structure of crystalline materials.
"My technique looks at atomic positions—who are neighbors, and where they are. Quite often you see that the local structure is different from the average structure," he said.
By improving atomic PDF accuracy and introducing a statistical method to analyze error, Egami was able to determine the structure of many scientifically and technologically important crystals, showing that local disorder at a nano-meter scale often governs the properties of materials.
"Functional materials—materials that do something, like [those found in] sensors or fuel cells—are complex. For instance, certain ceramics are insulating under most conditions, but under the right conditions they suddenly change into metallic conductors of electricity.
"This spectacular change of character is caused by subtle interaction between the atomic structure and electrons. The PDF method told us exactly what was happening and how to explain it," he said.
Egami received the American Crystallography Society 2003 Bertram Eugene Warren Diffraction Physics Award in recognition of his use of atomic PDF analysis of disordered crystals using pulsed neutrons and synchrotron x-rays.
Website contact information