RIVERSIDE, Calif. Physicists at the University of California, Riverside have taken an important step forward in developing a "spin computer" by successfully achieving "tunneling spin injection" into graphene.
An electron can be polarized to have a directional orientation, called "spin." This spin comes in two forms electrons are said to be either "spin up" or "spin down" and allows for more data storage than is possible with current electronics.
Spin computers, when developed, would utilize the electron's spin state to store and process vast amounts of information while using less energy, generating less heat and performing much faster than conventional computers in use today.
Tunneling spin injection is a term used to describe conductivity through an insulator. Graphene, brought into the limelight by this year's Nobel Prize in physics, is a single-atom-thick sheet of carbon atoms arrayed in a honeycomb pattern. Extremely strong and flexible, it is a good conductor of electricity and capable of resisting heat.
"Graphene has among the best spin transport characteristics of any material at room temperature," explained Roland Kawakami, an associate professor of physics and astronomy, who led the research team, "which makes it a promising candidate for use in spin computers. But electrical spin injection from a ferromagnetic electrode into graphene is inefficient. An even greater concern is that the observed spin lifetimes are thousands of times shorter than expected theoretically. We would like longer spin lifetimes because the longer the lifetime, the more computational operations you can do."
To address these problems, in the lab Kawakami and colleagues inserted a nanometer-thick insulating layer, known as a "tunnel barrie
|Contact: Iqbal Pittalwala|
University of California -- Riverside