Ann Gaudreaux, William & Mary News

Navy submarines monitor their under-sea surroundings with sonar, which uses a device called a transducer to convert soundwaves to electrical signals. At the heart of a transducer is a piezoelectric element, and getting at the heart of things piezoelectric is Henry Krakauer, professor of physics and director of the newly formed Center for Piezoelectrics Design (CPD).

Thanks to a grant from the Office of Naval Research, Krakauer and Shiwei Zhang, assistant professor of physics, will collaborate with other CPD members to research materials that can be more effective piezoelectrics.

Professor of Physics and director of the newly formed Center for Piezoelectrics Design, Henry Krakauer. Photo by Jim Gleason

Sound waves will cause any object to vibrate sympathetically, which minutely changes the object’s shape. Piezoelectric materials are special because, when they change their shape, they produce electrical signals that can be sent and received. Conversely, subjecting a piezoelectric material to electrical signals causes it to change shape and vibrate. This is the basis for a wide variety of important applications, including medical ultrasound imaging devices and ultrasonic scalpels.

The search for better piezoelectric materials has generally relied on costly and time-consuming trial-and-error testing of candidate materials, Krakauer said. The Center for Piezoelectrics Design will take a different approach, using computational modeling to develop new types of candidate materials and to screen them for desired properties before taking them into the laboratory. The research requires precise quantum mechanical calculations for these materials.

The Office of Naval Research supports long-range scientific research that can lead to innovations in fields relevant to present and future Navy needs, according to Krakauer. The grant of more than $1.4 million this year is renewable up to five years for a total of more than $6 million.

All known high-performance piezoelectrics are structurally and chemically complex materials, and the design of piezoelectrics requires an unprecedented degree of cooperation among the participating scientists. The CPD has been established to facilitate these efforts with the construction of a special cluster of computers, specialized software and a regular schedule of team meetings.

The CPD’s dozen senior scientists include members from the Carnegie Institution of Washington, the University of Arkansas, the University of Pennsylvania, Rutgers University and the U.S. Naval Research Laboratory. The group wants to understand the origin of the high-performance properties of currently used piezoelectrics, such as lead zirconate titinate (PZT), and to find or create new materials using computer simulation. CPD members will also develop new theories and algorithms for future investigations.

Solving the basic quantum mechanical equations using ‘first-principles’ methods is computationally very demanding, Krakauer said. We will use the results of the ‘first-principles’ calculations to construct simpler simulation tools, called effective methods, that can be used to study much larger collections of atoms. Therefore, we will be able to study things that you couldn’t study using the ‘first-principles’ approaches alone.

A high-end cluster of computers capable of executing several billion computer instructions per second will be supported through the grant and housed in the CPD’s operations area at the Applied Research Center in Newport News. Bernadette Kulas will manage the CPD there. People will do their intensive computing at the CPD and then use the Internet for post-processing at their home institution. The ‘lab’ will basically exist on the Internet, Kulas said.

We will also facilitate the availability of the software we develop to other research groups who want to use it. This will be a spin-off of the CPD, added Krakauer. The grant significantly strengthens basic materials science research at the College and has potential impact for technology in many areas of science, not just piezoelectrics.

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Updated July 3, 2003