Graphene, the ultra-thin, ultra-strong material made from a single layer of carbon atoms, just got a little more extreme. UBC physicists have been able to create the first ever superconducting graphene sample by coating it with lithium atoms.

Although superconductivity has already been observed in intercalated bulk graphite—three-dimensional crystals layered with alkali metal atoms, based on the graphite used in pencils—inducing superconductivity in single-layer graphene has until now eluded scientists.

“This first experimental realization of superconductivity in graphene promises to usher us in a new era of graphene electronics and nanoscale quantum devices,” says Andrea Damascelli, director of UBC’s Quantum Matter Institute and leading scientist of the Proceedings of the National Academy of Sciences study outlining the discovery.

Graphene, roughly 200 times stronger than steel by weight, is a single layer of carbon atoms arranged in a honeycomb pattern. Along with studying its extreme physical properties, scientists eventually hope to make very fast transistors, semiconductors, sensors and transparent electrodes using graphene.

“This is an amazing material,’” says Bart Ludbrook, first author on the PNAS paper and a former PhD researcher in Damascelli’s group at UBC. “Decorating monolayer graphene with a layer of lithium atoms enhances the graphene’s electron–phonon coupling to the point where superconductivity can be stabilized.”

Given the massive scientific and technological interest, the ability to induce superconductivity in single-layer graphene promises to have significant cross-disciplinary impacts. According to financial reports, the global market for graphene reached $9 million in 2014 with most sales in the semiconductor, electronics, battery, energy, and composites industries.

The researchers, which include colleagues at the Max Planck Institute for Solid State Research through the joint Max-Planck-UBC Centre for Quantum Materials, prepared the lithium-decorated graphene in ultra-high vacuum conditions and at ultra-low temperatures (-267 degrees Celsius or 5 Kelvin), to achieve this breakthrough.

UBC’s Quantum Matter Institute
UBC’s Quantum Matter Institute (QMI) is internationally recognized for its research and discoveries in quantum structures, quantum materials, and applications towards quantum devices. A recent $66.5-million investment from the Canada First Research Excellence Fund will broaden the scope of QMI’s research and support the discovery of practical applications for computing, electronics, medicine and sustainable energy technologies.

Study: Evidence for superconductivity in Li-decorated monolayer graphene in Proceedings of the National Academy of Sciences. Tracking number: 2015-10435R