Researchers have completely suppressed superconductivity in magic-angle graphene by screening interactions between electrons, helping resolve a long-running debate about the origin of the phenomenon.
Scientists from the National Graphene Institute at The University of Manchester have demonstrated that superconductivity in magic-angle graphene can be completely switched off by screening interactions between electrons. The finding provides strong evidence that electron interactions play a central role in the phenomenon and helps address a key question that has remained unresolved since superconductivity was first discovered in the material.
Magic-angle twisted bilayer graphene, created by stacking two sheets of graphene with a rotational offset of approximately 1.1 degrees, has become one of the most intensely studied quantum materials over the past decade. However, researchers have continued to debate what causes its superconductivity. While some theories propose that electrons themselves drive the pairing responsible for superconductivity, others suggest a more conventional mechanism involving vibrations of the atomic lattice.
In the new study, published in the journal Physical Review X, researchers developed a graphene device containing two twisted graphene bilayers separated by less than a nanometer while remaining electronically decoupled. This design enabled the team to control Coulomb screening more effectively than in previous experiments and directly test how superconductivity responds when electron interactions are weakened.
To read more, click here.