Graphene Breakthrough Could Replace Silicon Electronics with Majorana Fermion Equivalents

Researchers at the Georgia Institute of Technology (Georgia Tech) and the University of Tianjin have taken a big step towards bringing graphene-based electronics out of the lab and into the real world, as a replacement for silicon as fundamental physical constraints rear their heads and threaten to impede progress.

Moore's law is the observation by Intel co-founded Gordon Moore that the number of transistors, and thus performance or capabilities, of a high-end processor tends to double roughly every two years. While it was never intended as such, Moore's law has effectively become a hard target for the semiconductor industry — but as component sizes shrink physical constraints begin to make the next doubling exponentially more difficult. As a result, the race is on to find a solution — including looking at alternatives for silicon.

"Graphene's power lies in its flat, two-dimensional structure that is held together by the strongest chemical bonds known," Walter de Heer, professor at the Georgia Institute of Technology's School of Physics, explains of the material his team has been investigating as a potential silicon replacement. "It was clear from the beginning that graphene can be miniaturized to a far greater extent than silicon — enabling much smaller devices, while operating at higher speeds and producing much less heat. This means that, in principle, more devices can be packed on a single chip of graphene than with silicon."

Graphene, a material made up of a layer of carbon just one atom thick, has the potential to be a true wonder-material — but thus far has struggled to make its way out of the lab in particularly meaningful projects. Using chips made from silicon carbide crystals, the researchers were able to grow a layer of graphene then etch it through electron beam lithography — before welding it to the silicon carbide, creating a functional nanoelectronics device.

The breakthrough exposed something unexpected: Electric charges, which act like photons in an optical fiber, traveling for far further along the graphene edge before scattering than in previous attempts at graphene electronics. "What's special about the electric charges in the edges is that they stay on the edge and keep on going at the same speed," explains Claire Berger, physics professor, of the discovery, "even if the edges are not perfectly straight."

Te team's work suggests that the edge currents are carried by a quasiparticle with no charge and no energy, capable of moving without resistance and traveling on opposite sides of the graphene edge — despite being a single object. The theory: this quasiparticle may be the one proposed by Ettore Majorana in 1937 and which bears the physicist's name: the Majorana fermion. "Developing electronics using this new quasiparticle in seamlessly interconnected graphene networks is game changing," claims de Heer.

There is, as always, a catch: de Heer predicts that turning what they have developed in the lab into a functional electronics platform could take five to ten more years of research — though undeniably brings graphene a step closer to replacing silicon in the future.

The team's work has been published in the journal Nature Communications under open-access terms.