Researchers at Aalto University and the University of Jyväskylä showed that graphene can be a superconductor at a much higher temperature than expected, due to a subtle quantum mechanics effect of graphene's electrons.

The discovery of the superconducting state in twisted bilayer graphene spurred an intense debate among physicists regarding the origin of superconductivity in graphene. Although superconductivity was found only at a few degrees above the absolute zero of temperature, uncovering its origin could help understanding high-temperature superconductors and allow us to produce superconductors that operate near room temperature. Such a discovery has been considered one of the "holy grails" of physics, as it would allow operating computers with radically smaller energy consumption than today.

A research team from the University of Göttingen, together with the Chemnitz University of Technology and the Physikalisch-Technische Bundesanstalt Braunschweig, has investigated the influence of the crystal on which graphene is grown, on the electrical resistance of the resulting material.

Contrary to previous assumptions, the new results show that the process known as the ‘proximity effect’ varies considerably at a nanometre scale. To determine the electrical resistance of graphene at the smallest scale possible, the physicists used a scanning tunneling microscope (STM).

Researchers from Israel's Weizmann Institute and the UK's Manchester University have succeeded in imaging electrons' hydrodynamic flow pattern for the first time using a novel scanning probe technique. They have proven the longstanding scientific theory that electrons can behave like a viscous liquid as they travel through a conducting material, producing a spatial pattern that resembles water flowing through a pipe.

The results of this study could help developers of future electronic devices, especially those based on 2D materials like graphene in which electron hydrodynamics is important.

An international team of researchers from Spain, the U.S., China and Japan has found that superconductivity in bilayer graphene can be turned on or off with a small voltage change, increasing its usefulness for electronic devices. This follows previous findings regarding twisted bilayer graphene and its ability to exhibit alternating superconducting and insulating regions.

"It's kind of a holy grail of physics to create a material that has superconductivity at room temperature," University of Texas at Austin physicist Allan MacDonald said. "So that's part of the motivation of this work: to understand high-temperature superconductivity better."

Haydale has launched a range of graphene-enhanced prepreg materials for lightning-strike protection, utilizing functionalized graphene to improve the electrical conductivity.

The material has been developed in collaboration with Airbus UK, BAE Systems, GE Aviation and Element Materials Technology Warwick, within the NATEP-supported GraCELs project where the first iterations of materials were developed and subjected to lighting strike tests. The consortium is now looking to manufacture a demonstrator component using the materials developed to establish composite manufacturing protocols as a showcase part for commercial purposes.

Researchers at The Ohio State University, in collaboration with University of Texas, Dallas scientists and the National Institute for Materials Science in Japan, have found that graphene is more likely to become a superconductor than originally thought possible.

(A) Schematic diagram of device geometry. (B) Schematic diagram of moiré superlattice formed by the twisted graphene layers. Image from Science Advances

Graphene by itself can conduct energy, as a normal metal is conductive, but it is only recently that we learned it can also be a superconductor, by making a so-called ‘magic angle’ twisting a second layer of graphene on top of the first, said Jeanie Lau, a professor of physics at Ohio State and co-author of the paper. And that opens possibilities for additional research to see if we can make this material work in the real world.

A research team jointly led by University of Warwick and EMPA has tackled a challenging issue of stability and reproducibility in working with graphene, that meant that graphene-based junctions were either mechanically stable or electrically stable but not both at the same time.

Credit: University of Warwick

Graphene and graphene like molecules are attractive choices for electronic components in molecular devices, but have proven very challenging to use in large scale production of molecular devices that will work and be robust at room temperatures. The joint research team from the University of Warwick, EMPA and Lancaster and Bern Universities has reached both electrical and mechanical stability in graphene-based junctions.

A research team led by Rutgers University has discovered that in the presence of a moiré pattern in graphene, electrons organize themselves into stripes, like soldiers in formation. The team's findings could help in the search for quantum materials, such as superconductors, that would work at room temperature. Such materials would dramatically reduce energy consumption by making power transmission and electronic devices more efficient.

Left: image shows a moiré pattern in "magic angle" twisted bilayer graphene. Right: Scanning tunneling charge spectroscopy, shows correlated electrons. Credit: Rutgers University

"Our findings provide an essential clue to the mystery connecting a form of graphene, called twisted bilayer graphene, to superconductors that could work at room temperature," said senior author Eva Y. Andrei, Board of Governors professor in the Department of Physics and Astronomy in the School of Arts and Sciences at Rutgers UniversityNew Brunswick.

Stanford physicists recently observed a novel form of magnetism, predicted but never seen before, that is generated when two graphene sheets are carefully stacked and rotated to a special angle. The researchers suggest the magnetism, called orbital ferromagnetism, could prove useful for certain applications, such as quantum computing.

Optical micrograph of the assembled stacked structure, which consists of two graphene sheets sandwiched between two protective layers made of hexagonal boron nitride. (Image: Aaron Sharpe)

We were not aiming for magnetism. We found what may be the most exciting thing in my career to date through partially targeted and partially accidental exploration, said study leader David Goldhaber-Gordon, a professor of physics at Stanford’s School of Humanities and Sciences. Our discovery shows that the most interesting things turn out to be surprises sometimes.

Researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have designed a graphene device that switches from a superconducting material to an insulator and back again to a superconductor — all with a flip of a switch. The team shared that the device exhibits this unique versatility while being thinner than a human hair.

Views of the trilayer graphene/boron nitride heterostructure device as seen through an optical microscope. The gold, nanofabricated electric contacts are shown in yellow; the silicon dioxide/silicon substrate is shown in brown and the boron nitride flakes

"Usually, when someone wants to study how electrons interact with each other in a superconducting quantum phase versus an insulating phase, they would need to look at different materials. With our system, you can study both the superconductivity phase and the insulating phase in one place," said Guorui Chen, the study's lead author and a postdoctoral researcher in the lab of Feng Wang, who led the study. Wang, a faculty scientist in Berkeley Lab's Materials Sciences Division, is also a UC Berkeley physics professor.