Researchers at Northeastern University and Harvard University have conducted two experiments that shed light on why cold thin sheets of carbon offer no resistance to electric currents, bringing the possibility of practical room-temperature superconductors closer.
A team led by Kin Chung Fong at Northeastern University estimated a number with fellow physicist Abhishek Banerjee at Harvard University over dinner, sparking their interest in graphene’s properties. They focused on kinetic inductance, which might illuminate why some stacked layers of graphene become superconductive at low temperatures. Two experiments were conducted: one with two-layer graphene and another with three-layer graphene.
The research teams used innovative setups to measure kinetic inductance, exposing tiny graphene flakes to microwaves while varying properties like temperature. According to Joel Wang, a Massachusetts Institute of Technology researcher involved in the two-ply graphene experiment, measuring kinetic inductance was previously difficult due to limited production and experimental techniques.
The findings showed that superconducting currents in multilayer graphene exhibit unusual properties, such as being “stiffer” than predicted by conventional theories. Researchers attributed this anomaly to quantum geometry, specifically the shape of electrons’ wavefunctions. In trilayer graphene, similarities were found between kinetic inductance and behavior of different superconductors at higher temperatures.
Physicists believe these experiments may reveal key properties required for room-temperature superconductors, which could significantly reduce energy consumption. The study’s authors suggest that breakthroughs might also shed light on fundamental laws governing particles’ electric charges.
Researchers are now planning similar experiments with other thin superconductors, following the discovery of new two-dimensional materials exhibiting unusual superconducting properties.
Source: https://www.newscientist.com/article/2466930-the-superconductivity-of-layered-graphene-is-surprisingly-strange