Since it was first created in 2004, graphene – a sheet of carbon just one atom thick – has fascinated scientists as a kind of universal material: it’s bendable yet many times stronger than steel, it’s transparent, and conducts electricity.
Graphene already is being used in medical filters and specialty coatings, among a spectrum of current and possible applications.
Now it’s also helping engineers achieve the long-sought goal of superconductivity – transmitting electricity without losing any to resistance or “friction” in the wires that carry it.
In 2018, researchers at the Massachusetts Institute of Technology laid one sheet of graphene on top of another and twisted the top sheet by just 1.1 degrees.
The result has created an entire new field of research: twistronics.
When the top sheet was twisted by that small amount and an electronic current was applied, the two sheets switched from conducting electricity to insulating against it; then the material became a superconductor, transmitting electricity without losing any to resistance.
The two-layer device already is being used to make superconducting electronic switches, known as Josephson junctions, that are essential in quantum computers, the next generation of machines able to calculate orders of magnitude faster than today’s versions. The junctions also are essential in some devices that measure subtle magnetic fields and monitor electrical activity in the brain.
Challenges remain, such as holding the twisted sheet at the proper angle without wrinkling it and the daunting prospect of cooling the devices to near-absolute zero before they can work.
TRENDPOST: Until well into the 2030s, devices using twisted graphene will be limited to specialty uses, such as medical devices and quantum computers. But “twistronics” has shown scientists a way to make materials without chemistry, a feat never before achieved on such a wide-ranging scale of applications.
