MSE Professor and Student Spin Closer to Efficient Silicon Transistors

Ashutosh Tiwari and Nathan Gray

March 15, 2011 – University of Utah researchers built “spintronic” transistors and used them to align the magnetic “spins” of electrons for a record period of time in silicon chips at room temperature. The study is a step toward computers, phones and other spintronic devices that are faster and use less energy than their electronic counterparts.

“Electronic devices mostly use the charge of the electrons – a negative charge that is moving,” says Ashutosh Tiwari, an associate professor of materials science and engineering at the University of Utah. “Spintronic devices will use both the charge and the spin of the electrons. With spintronics, we want smaller, faster and more power-efficient computers and other devices.”

Tiwari and MSE Alum Nathan Gray (Ph.D., 2012) report their creation of room-temperature, spintronic transistors on a silicon semiconductor this month in the journal Applied Physics Letters. The research – in which electron “spin” aligned in a certain way was injected into silicon chips and maintained for a record 276 trillionths of a second – was funded by the National Science Foundation.

“Almost every electronic device has silicon-based transistors in it,” Gray says. “The current thrust of industry has been to make those transistors smaller and to add more of them into the same device” to process more data. He says his and Tiwari’s research takes a different approach.

“Instead of just making transistors smaller and adding more of them, we make the transistors do more work at the same size because they have two different ways [electron charge and spin] to manipulate and process data,” says Gray.