Friday, July 28, 2006

"QUANTUM: Spintronics research targets GaAs"

Hole-rich semiconductors like gallium arsenide could harness the quantum effect called "electron spin" for a new era of spintronic devices which store information on magnetic atoms inserted into a semiconductor's crystalline lattice. But the current technique of random doping of magnetic atoms makes adding spintronics capabilities a hit-or-miss process. Now researchers claim to have perfected a method of brewing exactly the right molecular arrangement. Using a scanning tunneling microscope to substitute magnetic (manganese) atoms for individual gallium atoms, Princeton University researchers were able to experiment with different crystalline lattice architectures to optimize spintronic capabilities. The researchers confirmed the optimal lattice architecture for a new spintonic material: gallium manganese arsenide. The researchers claim this is the first time atomic-level manipulations were used to verify theoretical predictions about the optimal atomic arrangement in a semiconductor. Moreover, the arrangement was achieved one atom at a time in a crystalline lattice. GaAs is a candidate for next-generation spintronic devices because of its very high electron mobility compared to silicon. By incorporating magnetic atoms into a gallium manganese arsenide semiconductor, the team said it hopes to separately control spin and charge to enable highly energetic spintronic devices.