Exfoliation of pencil lead graphite yields a 2D substance called graphene, which is as thin as a single atom. Carbon atoms are organized in a basic hexagonal arrangement, like chicken wire, to create the ultrathin material. Researchers have uncovered various amazing features in graphene’s single-layer form since it was originally isolated in 2004.
In 2018, MIT researchers revealed that a twisted bilayer structure with durable superconductivity may be created by stacking two graphene layers at a certain “magic” angle. Electrical currents lose no energy while passing through this highly sought-after material state. Recently, a comparable superconductive condition was discovered in twisted trilayer graphene—a configuration comprised of three graphene layers arranged at an exact, new magic angle.
Four and five graphene layers may now be twisted and layered at new magic angles to elicit strong superconductivity at low temperatures, according to the study team’s recent findings. Graphene’s multiple twisted and layered forms have been established as the first known “family” of multilayer magic-angle superconductors, as reported in Nature Materials on July 7, 2022. The researchers also discovered similarities and variances amongst members of the graphene family.
As a result of this new finding, practical, room-temperature superconductors may be possible. Using other naturally conductive materials, for example, to provide electricity without dissipating losses or create magnetically floating trains that operate without friction, may be possible if the qualities across family members were reproduced.
The initial discovery of magic-angle graphene was made by Jarillo-group, Herrero’s who discovered a bilayer structure comprising two graphene sheets put one over the other and partially offset at an exact angle of 1.1 degrees. At very low temperatures, this twisted arrangement called a moiré superlattice, turned the material into a robust and long-lasting superconductor.
It turned out that the material’s electrons had the same energy regardless of their momentum, which is known as a “flat band,” according to the researchers. Either in a “flat band” condition or at ultracold temperatures, the typically speeding electrons cumulatively slow down sufficiently to form Cooper pairs, which are crucial elements of superconductivity.