An impossible behavior in electrons? No thanks to graphene. They have captured electrons flowing through graphene like a liquid, reaching limits that physicists believed fundamentally impossible.
Graphene is not only stronger than steel and harder than diamond, it is even a better conductor than copper thanks, in part, to its two-dimensional structure. Now, a team of scientists from the National Graphene Institute has conducted a series of experiments that have revealed a new understanding of the physics of conductive materials by looking at the unusual motion of electrons in graphene.
In most metals, conductivity is limited by crystalline imperfections that cause electrons to frequently scatter like billiard balls as they move through the material. Experts have discovered, however, that electrons behave in a peculiar way in graphene, as if they flow like a liquid, making them incredibly conductive of energy.
This type of conductivity is known as superballistic flow, and it is evidence of a future revolution in the way electricity is conducted.
Move energy like a liquid
For decades, scientists had speculated that, in some circumstances, electrons could stop behaving as they normally did and collide so often that they actually began to move like a viscous fluid with all sorts of unique properties. As early as last year, researchers confirmed the phenomenon, showing for the first time that, even at room temperature, electrons within graphene could act as a fluid 100 times more viscous than honey.
Now the same team, led by Andre Geim, a physicist at the University of Manchester who won the 2010 Nobel Prize for his work on graphene, has shown that this liquid phenomenon of electrons is even more surprising than we thought.
By unlocking this fluid behavior, the experts were able to observe the electrons in graphene breaking a fundamental boundary for electrons in a normal metal, known as the Landauer ballistic boundary.
This is one of the first experimental confirmations to show just how powerful this new kind of physics could be and, more importantly, it also suggests that we might be on the brink of a whole new way of moving electricity through materials with a resistance close to zero.
Currently, this is something that superconductors can achieve, but their ability only emerges at temperatures below -267 ° C. However, in this latest experiment, physicists were able to observe this superballistic flow at a relatively hot temperature -123 °. C. In fact, the resistance decreased as the temperature increased, the opposite of what you would expect.
How does it work? Rather than increasing resistance, sometimes when electrons collide with each other they can actually start to work together and facilitate the flow of current.
Finding a way to conduct electricity more efficiently at higher temperatures is one of the “Holy Grails” of physics, as it would pave the way for ultra-efficient computers or power grids that do not lose 7% percent of their energy as hot.
For now we’ve only scratched the surface of how strange (and extraordinary) graphene really is.
This fantastic material could replace silicon in electronics, improve the efficiency of batteries, the durability and conductivity of touchscreens … an extraordinary range of possibilities.
Reference: R. Krishna Kumar et al. Superballistic flow of viscous electron fluid through graphene constrictions, Nature Physics (2017). DOI: 10.1038 / nphys4240
Image credit: University of Manchester
