Topological insulators make "spintronics" possible

"Quantum magic can make strange but useful semiconductors that are insulators on the inside and conductors on the surface."

Joel E. Moore, in ieee spectrum online, July 2011, describes how mathematical theory may make "spintronics" possible. "By 2006, three separate groups of mathematicians had discovered that it was possible, in theory, to produce materials that are insulators on the inside but conductors on the outside. The theorists concluded that these materials—called topological insulators because changes in their shape have no effect on their conductivity or quantum mechanical behavior—will make it simple to manipulate the quantum mechanical spin of an electron. That level of subatomic control would make it possible to use spin as the underpinning for computer logic that would outclass today’s microprocessors in both speed and fuel efficiency—or as the mechanism by which hard disks are written, read, or rewritten."

(Image: Aharon Kapitulnik and Zhanybek Alpichshev/Stanford University)