University of California scientists working at Los Alamos National Laboratory have developed a novel method for controlling and measuring electron spins in semiconductor crystals of GaAs (gallium arsenide). The work suggests an alternative--and perhaps even superior--method of spin manipulation for future generations of "semiconductor spintronic" devices.
In research published in todays issue of the scientific journal Physical Review Letters, Scott Crooker and Darryl Smith describe their use of a scanning optical microscope to acquire two-dimensional images of spin-polarized electrons flowing in semiconductor crystals mounted on an optical cryostat while using a miniature "cryogenic vise" to apply gentle pressure. By squeezing the crystal in a controlled manner, and without applying magnetic fields, the researchers were able to watch the electron spins rotate (or precess) as they flow through the crystal.
According to Crooker, "electrons, in addition to their negative electronic charge, also possess a magnetic "spin". That is, each electron behaves like a little bar magnet, with north and south poles. Electron spins in semiconductors are typically manipulated by applying a magnetic field, but weve found we can do the same thing, in a controlled fashion, using the "vise". And, the resulting degree of spatial spin coherence is remarkably more robust compared to the spin precession induced by a magnetic field."
Todd Hanson | EurekAlert!
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