(ScienceDaily) Condensed matter physicists Charles Kane and Eugene Mele considered the fate of graphene at low temperatures in 2005. Their work led to the discovery of a new state of matter dubbed a “topological insulator,” which would usher in a new era of materials science. “A topological insulator is a material that is an insulator in its interior but is highly conducting on its surface,” said UC Santa Barbara assistant physics professor Andrea Young. In two-dimensions, an ideal topological insulator would have “ballistic” conductance at its edges, Young explained, meaning that electrons traveling through the region would encounter zero resistance.according to Young, this work is one step closer to building an actual topological insulator with graphene. “Theoretical work has since shown that a graphene trilayer, fabricated in the same way, would lead to a true topological insulator.”
Most importantly, the devices realized by Island and Young can be easily tuned between a topological insulating phase and a regular insulator, which does not have conducting edge states.