Topological insulators (TI) are three-dimensional materials that conduct electricity on their surfaces, while the interior insulates. Research into a recently discovered class of materials shows they have the necessary characteristics to develop ultra-energy efficient electronics. Their surfaces are particularly unique because the motion of the electrons is “protected” by symmetry, meaning electrons will keep moving without scattering even when they encounter defects and contamination.
Electrons on the surface of TIs move so robustly scientists are trying to determine the best way to control or “tune” them in order to use them in next-generation electronics. Until now the only way to change the electronic state was to apply a magnetic or an electric field.
But research by physicists at the University of Wisconsin-Milwaukee (UWM) has revealed a new method. The team proved that surface conduction on a bismuth selenide TI (Bi2Se3) can be enhanced or destroyed, depending on the kind of stress applied to the material at certain locations, called grain boundaries.