Researchers developed a way to control electron spin using pure-electric means

Researchers from the University of Cincinnati has developed a novel way to control the spin of electrons using pure electric means. Before the researchers made their breakthrough, the only way to control the spin of electrons was by using local ferromagnets in device architectures. The scientists say that this technique results in design complexities when the demands for electronics require smaller and smaller transistors.

The team used a device called a quantum point contact. Philippe Debray, research professor in the Department of Physics in the McMicken College of Arts & Sciences said "We used a quantum point contact — a short quantum wire — made from the semiconductor indium arsenide to generate strongly spin-polarized current by tuning the potential confinement of the wire by bias voltages of the gates that create it."

He continued saying, "The key condition for the success of the experiment is that the potential confinement of the wire must be asymmetric — the transverse opposite edges of the quantum point contact must be asymmetrical. This was achieved by tuning the gate voltages. This asymmetry allows the electrons — thanks to relativistic effects — to interact with their surroundings via spin-orbit coupling and be polarized. The coupling triggers the spin polarization and the Coulomb electron–electron interaction enhances it."

The team says that the next step in their research is to achieve the same results at higher temperatures using a different material like gallium arsenide.

Posted: Oct 29,2009 by Ron Mertens