Physicists Discover World’s First Naturally Occurring Topological Insulator
[Philip Lelyveld comment: this is mind-boggling! Nature is amazing.]
The new material is a grey, metallic mineral called Kawazulite which is made of bismuth, tellurium, selenium, and sulphur.
Topological insulators are one of the more exciting new materials in science. This stuff is odd because is a conductor on the surface but an insulator inside, rather like a block of ice in which melting water flows around the outside but is trapped as a solid in the middle.
But topological insulators have another property. The electrons flowing over the surface of a topological insulator are all aligned in a specific way. In fact, their “spins” are locked at right angles to their direction of motion.
This spin-momentum locking means that the electrons are immune from the buffeting they would get inside an ordinary conductor. Instead, the electrons can move through perfect topological insulators with 100 percent efficiency, even at room temperature.