Scientists find asymmetry in topological insulators

New research shows that a class of materials being eyed for the next generation of computers behaves asymmetrically at the sub-atomic level. This research is a key step toward understanding the topological insulators that may have the potential to be the building blocks of a super-fast quantum computer that could run on almost no electricity.

Scientists from the Energy Department's National Renewable Energy Laboratory contributed first-principles calculations and co-authored the paper "Mapping the Orbital Wavefunction of the Surface States in 3-D Topological Insulators," which appears in the current issue of Nature Physics. A topological insulator is a material that behaves as an insulator in its interior but whose surface contains conducting states.

In the paper, researchers explain how the materials act differently above and below the Dirac point and how the orbital and spin texture of topological insulator states switched exactly at the Dirac point. The Dirac point refers to the place where two conical forms – one representing energy, the other momentum – come together at a point. In the case of topological insulators, the orbital and spin textures of the sub-atomic particles switch precisely at the Dirac point. The phenomenon occurs because of the relationship between electrons and their holes in a semiconductor.

This research is a key step toward understanding the topological insulators like bismuth selenide (Bi2Se3), bismuth telluride (Bi2Te3), antimony telluride (Sb2Te3), and mercury telluride (HgTe) that may have the potential to be the building blocks of a quantum computer, a machine with the potential of loading the information from a data center into the space of a laptop and processing data much faster than today's best supercomputers.