“We don’t have a lab,” Reed says from his Stanford office. “We’re a purely theoretical modeling group.” Stanford’s Evan Reed is an assistant professor of materials science and engineering.
But forget labs crammed full of impressive arrays of stainless steel—ovens, burners, vacuum chambers, and pipes, because Reed is part of a new subsection of an age-old field that dates to when humans first melted and married metals to make new and better materials. Unlike the metallurgists of the past, however, Reed does not create new materials, he only theorizes about them and then simulates them on the computer. His goal is to point others in promising directions, saving those practical materials scientists countless years and dollars in experimental legwork.
Reed’s particular brand of materials science has been sparked by two recent advances. The first, of course, is in computer power that allows him to fiddle with and test the atomic structures without actually creating the materials. The second emerged only in 2004. It came in the form of graphene, a Nobel-recognized miracle material that has since reshaped engineering at the nanoscale.
Graphene is formed of a single layer of carbon atoms arranged in a honeycomb-like hexagonal pattern. At just one atom thick, it’s so thin that it is said to have no thickness at all—it is a two-dimensional (2D) material. Best of all, graphene possesses remarkable physical properties. It is stronger than steel. It conducts electricity and heat. It is transparent. And it doesn’t melt until temperatures approach those at the surface of the sun.
Most of graphene’s amazing properties are due to its 2D structure. Graphene, after all, is just a single layer of graphite, the same material in pencil lead, but it has birthed an entire new field known as 2D engineering.
“We’re interested in what’s special about 2D materials that we can’t do in 3D,” Reed says. “We’re looking for novel ways to store data, to make switches and transistors and things like that.”
One promising 2D material that Reed has focused on recently is molybdenum ditelluride. Like graphene, it is a single layer thick, but its crystal layer is made up of molecules, not individual atoms.
Thanks to simulations, for those Reed uses open-source modeling software with heavily modified code, they learned that when static electricity, like the sort that gives you a shock when you shuffle across a carpeted floor, is infused into molybdenum ditelluride, the material changes atomic structure. In essence, it gets turned “on.” Then, when the electrons are stripped away, it returns to an “off” state. Intriguingly, in the “on” state, molybdenum ditelluride conducts electricity. In the “off” state, it does not.
In effect, Reed’s group identified a new nanoscale switch. It is like a light switch, only 10,000 times thinner than a sheet of paper. Think next-generation foldable, flexible, wearable, and highly efficient phone screens and other new-age electronic circuits many times smaller than silicon devices could ever hope to be.