These are called 'topological insulators'

Mar 17, 2010 20:01 GMT  ·  By
Topological insulators could be the next testing ground for particle physics
   Topological insulators could be the next testing ground for particle physics

According to a new investigation presented at a recent scientific conference, it would appear that a class of very little-studied materials known as topological insulators may hold the key for physicists gaining new insight into exotic particles that have thus far only been hypothesized to exist. They have never been demonstrated to practically exist, but the amazing properties that these underdog materials have might make this happen for science. Details of the approach were presented on March 14 in Portland, Oregon, at the meeting of the American Physical Society, Nature News reports.

These materials are remarkable for their amazing property to conduct electrons (as in electrical currents) on their outside surface, while at the same time being insulators on the inside. A team of German researchers from the University of Wurzburg, led by expert physicist Laurens Molenkamp, managed to create a mercury telluride (HgTe) topological insulator that they say is advanced enough to put the theory about these exotic particles to the test. The group wants to use the material to test for the odd predictions of quantum field theory.

This is a version of the more commonly-known quantum mechanics and is widely employed in quantum physics. According to theory, a number of small, exotic particles exist in the Universe, which could have significant applications in fields such as spintronics and quantum computers. However, discovering a way to test whether these particles actually exist in reality has proven to be very difficult. The new HgTe insulator is apparently thick enough, the team says, to test for these predictions with a high degree of success.

The reason for why these topological insulators are so suitable for this kind of research is the fact that they allow electrons to pass through in a very peculiar manner. Each electron carries with it a quantum spin, classified as being either “up” or “down”. Particle physicists say that, usually, the spin is independent of the paths the electrons take as they move. This is not true inside these insulators, where the spin and the directions of these elementary particles are tightly-related to each other, explains Stanford University theoretical physicist Shoucheng Zhang.