Researchers at Lawrence Berkeley Laboratory have discovered that sodium bismuthide can exist as a form of matter called a “three-dimensional topological Dirac semi-metal” (3DTDS). A 3DTDS is a natural three-dimensional counterpart to grapheme, with similar or even better electron mobility and velocity, according to the researchers. Graphene and topological insulators are crystalline materials that are electrically insulating inside but conducting on the surface, allowing them to function as transistors and other electronic devices. They feature 2-D Dirac fermions, which give rise to extraordinary and highly desirable physical properties. While sodium bismuthide (Na3Bi) is too unstable to be used in devices without proper packaging, it has initiated the search for and development of other 3DTDS materials more suitable for everyday devices. Sodium bismuthide can also be used to demonstrate potential applications of 3DTDS systems, which may offer advantages over planar graphene. A 3DTDS system may also open possibilities to other novel physical properties for future electronic technologies and as an ideal platform for applications in spintronics.
Source: newscenter.lbl.gov/news-releases/2014/01/16/natural-3d-counterpart-to-graphene-discovered
