Researchers have found that a small stretch is enough to unleash the exotic electrical properties of a recently discovered topological insulator, unshackling a behavior previously locked away at cryogenic temperatures.The compound, called samarium hexaboride, has been studied for decades. But recently it has enjoyed a surge of renewed interest as scientists first predicted and then discovered that it was a new type of topological insulator—a material that banishes electrical currents from its interior and forces them to travel along its periphery. That behavior only emerges at around 4 degrees above absolute zero, though, thwarting potential applications.Now, experimentalists at the University of California, Irvine (UCI), working with JQI Fellow Victor Galitski and former JQI postdoctoral researcher Maxim Dzero (now at Kent State University), have found a way to activate samarium hexaboride’s cryogenic behavior at much higher temperatures. By stretching small crystals of the metal by less than a percent, the team was able to spot the signature surface currents of a topological insulator at 240 K (minus 33 C)—nearly room temperature and, in any case, a far cry from 4 K. The currents even persisted once the strain was removed.
