Single-layer Graphene As A Superconductor
Imagine computers that are not only smaller and faster, but also infinitely more powerful than anything we have today; biosensors 100 times more sensitive than semiconductor based devices, enabling a more intricate imaging of brain activity; or supercurrent-based ultrasensitive magnetometers and advanced digital logic circuits. These are only a few of the foreseeable implications of what appears to be a technological breakthrough. Scientists at UBC’s Quantum Matter Institute were able to use single-layer graphene as a superconductor, which promises to pave the way for a new era of graphene electronics and nanoscale quantum devices.
The First Experimental Realization
“This is the first experimental realization of superconductivity in graphene,” explained Andrea Damascelli, director of the Quantum Matter Institute (QMI).
“Most materials we know are bulk three dimensional crystals, such as graphite” but “graphene is an atomically-thin single layer of carbon atoms.” It possesses only two dimensions, while graphite is an infinite stacking of those thin layers.
Previous experiments in this direction have utilized three-dimensional bulk graphite crystals with alternating layers of carbon and alkali metal atoms.
Being Only Two Dimensional
“If you look at what graphene is enabling now, in terms of applications, there is already an ongoing technological revolution,” said Damascelli. “Being only two dimensional, graphene offers a unique platform to exploit quantum mechanical properties in the next generation of quantum devices for future technologies. And because it is a flexible and flat conductor, it is also used for making displays for durable, foldable electronics. The big interest in graphene comes from the low dimensional environment its electrons are confined to, which makes graphene’s electronic properties much richer than those of conventional metals and semi-conductors.”
“The next step is to combine the quantum physics of a two dimensional sheet of atoms with an additional property like superconductivity,” he adds. “If you are really able to make large displays, flexible electronics, and ultrasensitive sensors based on graphene, you would be looking at a technological revolution. If you add superconductivity to it, the potential gets even bigger.”
Proof Of Principle
He described this experiment as a proof of principle, the first demonstration that superconductivity – conductivity without any dissipation or resistance – can be induced in monolayer graphene.
“I go by analogy. We’ve seen many major technological revolutions over the past decades. The one that has had the largest impact was the inception of the semiconductor era. Without semiconductors you wouldn’t have computers or any mainstream electronics. An ever further reaching revolution I imagine will take place with the exploitation of quantum materials. In the case of the discovery of graphene, improving its performances and adding new properties, like turning graphene into a superconductor, will have a huge impact,” said Damascelli.
This breakthrough could ultimately change “the whole game.” Graphene holds the promise of being the platform that enables the new functionalities many future technologies will need. It may be used to develop faster transistors, infinitely more powerful electronic architectures, sensors and transparent electrodes, with broad technological potential in communication, computing and sustainable energy technologies. However there is a lot of work to be done before these quantum devices can be incorporated into emerging technologies.
Culmination of Five Years of Work
This breakthrough is the culmination of five years of work at UBC’s Quantum Matter Institute. QMI researchers have been working together with one of Germany’s premiere research centers, the Max Planck Institute for Solid State Research in Stuttgart, under the aegis of the Max-Planck UBC Centre for Quantum Materials funded in Vancouver in 2012.
“Without this concerted, collaborative effort with Max Planck researchers, we would have not been able to achieve this exciting result,” said Damascelli. Researchers and students from both institutions took part in the project. The Max Planck Institute provided the pristine graphene samples that were used here.
The Next Seven Years
UBC’s Quantum Matter Institute is internationally recognized for its research and discoveries in quantum structures, quantum materials, and applications towards quantum devices. QMI, as one of five nationwide selected recipients, received a recent $66.5 million investment from the Canada First Research Excellence Fund. This investment will be used over the next seven years to enable UBC’s Quantum Matter Institute to expand the scope of its research effort, taking it from proof of concept to knowledge creation and translation to technology.
“This funding will give us the resources and agility to really take advantage of these new concepts and ideas and exploit them in the next generation of devices,” said Damascelli.
The next step of this research endeavor is to engineer a superconducting graphene monolayer that is stable under ambient pressure and temperatures.