Using Graphene to Spin Electrons in New Directions
Electrons, like almost everything in life, are lazy. It has long been known that when traveling through conductive material, electrons always take the easiest route - that is, the path of least resistance. However, just like with people, the right kind of encouragement can make electrons take the harder road. Now, experts from MIT have discerned that graphene might be the life coach electrons have been waiting for.
Details on this discovery were published just this week in the prestigious journal Science.
According to the study, researchers from the Massachusetts Institute of Technology (MIT) found that when a two-dimensional array of perfectly structured carbon nanotubes - called graphene - is place atop another sheet of material, the electrons inside that material can be encouraged to move in new directions.
This could potentially induce a sideways flow, or even cause two currents to flow alongside one another in opposite directions - something that could lead to new and highly efficient technologies.
"It is quite a fascinating effect, and it hits a very soft spot in our understanding of complex, so-called topological materials," study co-author Andre Geim of MIT said in a university release. "It is very rare to come across a phenomenon that bridges materials science, particle physics, relativity, and topology."
In their work, Geim and his colleagues reportedly laid a sheet of graphene over a layer of boron nitride - a two-dimensional material that forms a hexagonal lattice structure similar to what graphene makes. Interestingly, when perfectly aligned, the two materials form a "superlattice" that can behave like a semiconductor.
And what makes this superlattice unique is that electrons flowing through it acquire what the researchers like to refer to as "a built-in vorticity, essentially placing a spin on each electron to nudge it in a new direction.
With enough controlled nudges, the researchers could carefully angle electron flow through the material to achieve astounding ends. For instance, by causing electrons to flow in opposite directions - canceling out each other's electrical charge - can produce a "neutral, chargeless current."
It is even suggested that this could be used in "spintronics," in which electronic information is not interpreted from the electrons themselves, but from their prescribed spin.
"It is widely believed that new, unconventional approaches to information processing are key for the future of hardware," added senior author Leonid Levitov.
This new technique, he says, is one such novel approach with great potential.