September 10, 2006
Spintronics and quantum computer without superconducting magnets
Physicists at the U.S. Department of Energy's Argonne National Laboratory have devised a potentially groundbreaking theory demonstrating how to control the spin of particles without using superconducting magnets — a development that could advance the field of spintronics and bring scientists a step closer to quantum computing.
The physicists theorize that spin can be induced and manipulated by running a current through gallium arsenide, a common semiconductor, in what is known as spin-3/2 hole systems, which previously have been little studied. Hole systems are “missing electrons,” while the fraction 3/2 refers to the magnitude of the spin. Spin-3/2 hole systems are created in semiconductors by “doping” — introducing impurities that have one less electron compared to the host material.
Geometry also must play a crucial role in spin manipulation, according to the researchers. They propose development of a nano-sized and L-shaped device that allows for the exploitation of the newly discovered effects in spin-3/2 hole systems.
Spintronics and wikipedia