SCIENCE

Kawakami explained that, theoretically, graphene has the potential for extremely long spin lifetimes.

“This lifetime could be microseconds long,” he said. “A long lifetime is a special property of graphene, making it a very attractive material for a spin computer.”

Growing insulating barriers on graphene is neither a simple nor easy process. The insulator tends to form clumps on the graphene sheet, due in part to graphene’s reluctance to form strong bonds with materials. To circumvent the problem of clumping, in their experiments the Kawakami team layered the graphene sheet with titanium (about half an atom thick) using a method called molecular beam epitaxy. The titanium layer, the researchers found, prevented the insulator from clumping on graphene or sliding off it.

Next in the research, the Kawakami lab plans to demonstrate a working spin logic device

Han, a recipient of the Leo Falicov Award from the American Vacuum Society, and Kawakami were joined in the study by Kyle Pi, Kathy McCreary, Yan Li, Jared Wong, and Adrian Swartz of UCR. Grants to Kawakami from the National Science Foundation and the Office of Naval Research supported the study.

Wei Han (left) is a graduate student working in the lab of Roland Kawakami (right), an associate professor of physics and astronomy at UC Riverside. The machine in the back is the molecular beam epitaxy chamber, where the researchers grew the titanium and the tunnel barriers. Photo credit: UCR Strategic Communications.

Wei Han (in blue shirt) and his advisor, Roland Kawakami, analyze data from their experiments. Photo credit: UCR Strategic Communications.

RELATED LINKS

• More about Roland Kawakami
• Department of Physics and Astronomy
• Physical Review Letters

ADDITIONAL CONTACTS

• Roland Kawakami
• Wei Han