Graphite, the soft material found inside ordinary pencils, may seem simple, but scientists have discovered that it can behave in remarkable ways when examined at the atomic level.
Researchers from the Massachusetts Institute of Technology (MIT) have found that a special form of graphene, which comes from graphite, can exist in several different superconducting states.
Even more surprising, some of these states become stronger when placed in a magnetic field instead of being destroyed by it.
The findings, published in the journal Nature, could help scientists better understand superconductivity, one of the most fascinating areas of modern physics.
Superconductivity is a special state in which electricity flows through a material with no resistance.
In normal wires, some electrical energy is lost as heat. In a superconductor, however, electricity moves without losing energy.
This property could one day improve power grids, medical scanners, quantum computers, and many other technologies.
Thousands of materials are known to become superconductors under certain conditions. However, it is very unusual for one material to have several different kinds of superconductivity.
The MIT team studied rhombohedral graphene, a naturally occurring form of graphene found inside graphite. Graphene is an extremely thin sheet made from a single layer of carbon atoms arranged in a honeycomb pattern. In rhombohedral graphene, four or five graphene layers are stacked like tiny stair steps.
To obtain these samples, the researchers carefully peeled thin layers from ordinary graphite using adhesive tape. They then searched for the rare staircase-like structure under powerful microscopes before carrying out detailed experiments.
The scientists changed the number of electrons inside the graphene by applying electrical voltage. They also cooled the material to extremely low temperatures and exposed it to powerful magnetic fields.
As they adjusted the electron density, they discovered four different superconducting states. Three of these states remained superconducting even when exposed to magnetic fields as strong as 9 tesla, which is about 180,000 times stronger than Earth’s magnetic field.
This surprised the researchers because magnetic fields usually destroy superconductivity. Normally, superconductivity happens when electrons pair together and move through a material without resistance. A magnetic field usually breaks these pairs apart, causing superconductivity to disappear.
Even more unexpectedly, one superconducting state actually became stronger when the magnetic field was applied in a certain direction. The graphene remained superconducting at a higher temperature than scientists normally expected, and it could carry much more electrical current before losing its superconducting ability.
The researchers are not yet sure why this happens. One possible explanation is that the electrons may be pairing together in a different way than in ordinary superconductors. Instead of having opposite magnetic spins, the paired electrons may have spins pointing in the same direction. If this is true, magnetic fields would no longer pull the pairs apart so easily.
Although much more research is needed, the discovery shows that even one of the simplest elements on Earth—carbon—can display surprisingly complex behavior when its atomic structure is carefully controlled.
The team believes these findings could lead to a deeper understanding of superconductivity and help scientists design entirely new quantum materials in the future.
While practical applications may still be many years away, the work demonstrates how studying ordinary materials in extraordinary detail can uncover completely unexpected properties that may one day support next-generation electronics, quantum technologies, and highly efficient energy systems.
