The unique atom-thick form of carbon known as graphene continues to amaze Researchers studying it, and one of the latest graphene studies found electrons move like slow-pouring honey as they pass through the material.
When passing through metals, electrons move like golf balls on a miniature golf course, occasionally being reflected by imperfections in the metal. However, a new study from University of Manchester Scientists discovered electrons moving through graphene in a slow, flowing manner.
The possibility a highly-viscous circulation of electrons in metals was predicted many decades ago but despite several attempts, were never identified, until this new study. The detection and analysis of this effect is expected to increase knowledge of the counterintuitive particle motion, a scientific area lacking significant understanding and mathematical solutions.
Electrons have been thought to move through graphene like they move through metals, in a ballistic manner where trajectory is affected by boundaries or imperfections. According to the new study, published in the journal Science, the reality is quite different from the theoretical.
The study team found an electric current flowing through graphene did not move with its applied electric field, as seen in other materials. Instead, electrons move backwards creating whirlpools where circular flows developed. Similar behavior is commonly seen in liquids, like water flowing around rocks in a stream.
In the study, the Researchers assessed the viscosity of this unusual flow in graphene. The study team found the electron flow was about 100 times more viscous than room-temperature honey.
The discovery could be crucial for learning more about how graphene and other materials behave at increasingly smaller sizes, research that is necessary for the semiconducting industry. The breakthrough also questions our current knowledge of the physics of very conductive metals, particularly graphene itself.
The concurrent presence of such apparently incompatible qualities, with electrons acting like golf balls and a liquid in the same kinds of material, encourages an essential rethinking around our knowledge of material qualities, the study team said.
Giving decades long efforts to find even minor signs of a viscous flow in metals, we were flabbergasted that graphene exhibited not just some small blip on an experimental curve but the clear qualitative effect, a large backflow of electric current.
Marco Polini, Study Author, the Instituto Italiano di Techologia
Study author Andre Geim, a Graphene Researcher at the University of Manchester, noted that the wonder material continues to amaze even people who study it every day.
Now we need to think long and hard how to connect such contradictory behavior as ballistic motion of electrons, which is undoubtedly seen in graphene, with this new quantum weirdness arising from their collective motion. A strong adjustment of our understanding of the physics is due.
Andre Geim, a Graphene Researcher, the University of Manchester
The new study comes after a report published in 2016 found electrons passing through graphene can be refracted, like a beam of light passing through glass. Given that light can be manipulated by optical devices like prisms, the findings of the 2016 study could lead to the creation of new electron switches based on the principles of optics, not the principles of electronics.
Cory Dean, an Author of that study and an Assistant Professor of Physics at Columbia University, said electron switches based on optical lensing to could be dramatically more efficient than conventional switches that make up computer chips, as it would address a critical bottleneck to achieving faster and more efficient electronics.
“These findings could also enable new experimental probes,” Dean said in a statement. “For example, electron lensing could enable on-chip versions of an electron microscope, with the ability to perform atomic scale imaging and diagnostics. Other components inspired by optics, such as beam splitters and interferometers, could additionally enable new studies of the quantum nature of electrons in the solid state.”