This emerging field focuses on harnessing the magnet-like spin property of electrons to produce electronics ranging from computers to cell phones that are faster, yet use less energy than today's power-hogging devices.
The highly competitive funding award, designed to support the integrated research and educational activities of faculty early in their careers, is bestowed on those scientists and engineers deemed most likely to become the academic leaders of the 21st century. Fewer than 20 percent of the proposals submitted by faculty from across the nation to the annual competition are funded.
The five-year, $400,000 award will support Appelbaum's research and companion education project on silicon spintronics.
“It was really great to receive this award,” Appelbaum says. “It will enable us to continue our work to prove that silicon--the world's top semiconductor--can be used in spintronic applications. Spintronic devices will offer a number of advantages in the future,” Appelbaum notes. “These lower-power, instant-on electronics will allow increased device portability and are especially important in light of today's increasing energy costs and its environmental impact.”
Silicon is the workhorse material of the electronics industry, the transporter of electrical current in computer chips and transistors. Silicon also had been predicted to be a superior semiconductor for spintronics, yet demonstrating the element's ability to conduct the spin of electrons, referred to as “spin transport,” had eluded scientists until Appelbaum and his research group, with a colleague from Cambridge NanoTech, published their results in the scientific journal Nature in May 2007.
The UD research group made international headlines as the first to demonstrate spin transport in silicon using a novel hot-electron detection technique.
Appelbaum's research group then showed how their device design could be used as a spin field-effect transistor. The design was featured on the cover of the scientific journal Applied Physics Letters in June 2007.
More recently, Appelbaum and his team showed that an electron's spin can be transported a marathon distance in the world of microelectronics--through a 350-micron-thick silicon wafer. That major advance was reported in the Oct. 26, 2007, issue of Physical Review Letters, published by the American Physical Society.
The former research was funded by grants from the U.S. Office of Naval Research and the Defense Advanced Research Projects Agency (DARPA) of the U.S. Department of Defense.
Now, with NSF's support, Appelbaum and his group will continue to explore the fundamental development of the silicon chips, transistors and integrated circuits required for a potential new industry. Ultimately, the research may lead to the development of a whole new logic architecture for electronics, Appelbaum says.
“While almost all work in the field has focused on compound semiconductors, there are clear benefits from leveraging the enormous existing capital investment in silicon,” Appelbaum says. “Furthermore, silicon has an intrinsically long spin lifetime, making it even more attractive for applications where spins must survive through many clock cycles and across complex circuits,” he says.
A complementary education component to the research project will include the training of graduate students and under-represented undergraduates in diverse aspects of science and engineering, including semiconductor device design, processing and measurement, and spintronics.
Also, research fellowships for minority undergraduate students will be fostered through a partnership with the local Louis Stokes Alliance for Minority Participation (LSAMP) and the Resources to Insure Successful Engineers (RISE) program at UD. Summer research internship opportunities for Delaware high school teachers will be offered, too, according to Appelbaum.
“The education component is designed to help us advance UD's research strengths in engineering and spintronics, as well as in nanotechnology,” Appelbaum says. “By exposing high-school teachers to modern nanotechnology concepts, we hope to excite their students' interest in pursuing advanced technology degrees.”
Appelbaum also plans to offer his successful course “Magnetism and Spintronics” (ELEG423) through a distance-learning format.
Appelbaum earned his bachelor's degree summa cum laude in physics and mathematics at Rensselaer Polytechnic Institute and his Ph.D. in physics at the Massachusetts Institute of Technology. He was a postdoctoral fellow at Harvard University for one year before joining the UD faculty in 2005.
Appelbaum is the author or co-author of more than 30 peer-reviewed journal articles. He is a member of the Materials Research Society and a life member of the American Physical Society.
Article by Tracey Bryant
Photo by Jon Cox