14 DAY TRIAL // An international team of scientists has recently managed to achieve an incredible goal in graphene research. They were able to produce pseudo-magnetic fields several times stronger than the strongest magnetic fields ever obtained in the lab. All of this was possible through applying the correct type of pressure and strain to a patch of the single-atom-thick carbon compound. Though discovered only a few years ago, the material is heralded as the potential replacement of silicon in today's electronics devices.
The team behind the investigation was led by expert Michael Crommie, who is a professor of physics at the University of California in Berkeley (UCB). He is also a faculty senior scientist at the US Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) Materials Sciences Division. “We have shown experimentally that when graphene is stretched to form nanobubbles on a platinum substrate, electrons behave as if they were subject to magnetic fields in excess of 300 tesla, even though no magnetic field has actually been applied. This is a completely new physical effect that has no counterpart in any other condensed matter system,” the team leader says.
“For over 100 years people have been sticking materials into magnetic fields to see how the electrons behave, but it’s impossible to sustain tremendously strong magnetic fields in a laboratory setting,” Crommie reveals. He adds that the strongest magnetic fields ever created reached only 85 tesla before blowing themselves apart, due to the excessive forces they develop. The thing about the latest accomplishment is that the research team managed to make electrons behave as if they were subjected to 300-tesla magnetic fields without actually applying any magnetic fields to them. The behavior was accomplished by stretching graphene the right way.
Details of the new work appear in a paper entitled “Strain-induced pseudo-magnetic fields greater than 300 tesla in graphene nanobubbles,” which is published in the July 30 issue of the esteemed journal Science. The research was made possible through grant money from the DOE Office of Science and the Office of Naval Research (ONR). “Controlling where electrons live and how they move is an essential feature of all electronic devices. New types of control allow us to create new devices, and so our demonstration of strain engineering in graphene provides an entirely new way for mechanically controlling electronic structure in graphene. The effect is so strong that we could do it at room temperature,” Crommie reports.