Twisted physics is what happens when two layers graphene are tilted at the magic angle.
“Last year, scientists demonstrated that twisted bilayer graphene—a material made of two atom-thin sheets of carbon with a slight twist—can exhibit alternating superconducting and insulating regions.
Now, a new study in the journal Nature by scientists from Spain, the U.S., China and Japan shows that superconductivity can be turned on or off with a small voltage change, increasing its usefulness for electronic devices.
“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.”
The discovery is a significant advance in an emerging field called Twistronics, whose pioneers include MacDonald and engineer Emanuel Tutuc, also from The University of Texas at Austin. It took several years of hard work by researchers around the world to turn MacDonald’s original insight into materials with these strange properties, but it was worth the wait.
The strategy MacDonald and Bistritzer employed proved successful. The surprise came later. When they applied their method to twisted bilayer graphene, a system consisting of two layers of carbon atoms, they found that at a very specific angle of about 1.1 degrees—which they dubbed the “magic angle”—the electrons behaved in a strange and extraordinary way, suddenly moving more than 100 times more slowly.
Why this was the case and what it would mean for science would take years to discover.”
Source: Phys Org. See also A Physics Magic Trick: Take 2 Sheets of Carbon and Twist
Image: When the two layers of bilayer graphene are twisted relative to each other by 1.1 degrees — dubbed the “magic angle” — electrons behave in a strange and extraordinary way, suddenly moving more than 100 times more slowly. Illustration credit: David Steadman/University of Texas at Austin. Credit: David Steadman/University of Texas at Austin