MIT scientists have discovered something that shouldn’t exist: a material that performs electricity while acting as a magnet without resistance.
This “chiral superconductor” was found to be hidden in ordinary graphite, the same carbon-based material used in pencil lead. This discovery, published today in nature, challenges a century-old assumption that magnetism and superconductivity are incompatible, such as oil and water.
This discovery comes from experiments with rhombus graphene, a special arrangement of carbon atoms stacked like stairs. When cooled to only 300 mm (almost absolute zero), the material exhibits zero resistance while maintaining its magnetic properties.
Break physical rules
“The general legend is that superconductors don’t like magnetic fields,” said Long Ju, assistant professor of physics at MIT and senior author of the study. “But we think this is the first superconductor observed for a magnet with such direct and simple evidence.”
The discovery overturned decades of established physics. Since 1911, scientists have known that superconductors repel magnetic fields through the Meissner effect. This magnetic repulsion is the reason for the activation of magnetic suspension trains, where superconducting rails push the magnetized car away.
However, MIT’s materials are completely different. When the researchers apply an external magnetic field and scan it from the negative to the front (such as flip between the North Pole and the South Pole), the material switches between two different superconducting states while maintaining zero resistance.
Graphite connection
The team was not initially looking for magnetic superconductors. They are studying eight-man rhombus graphene – sheets of carbon atoms arranged in offset staircase patterns. This structure occasionally forms tiny pockets in ordinary graphite.
Most graphite contains millions of graphene sheets that accumulate in conventional alignment. However, these rare rhombus regions, similar to misaligned components, create completely different electronic properties.
“If this is a conventional superconductor, it will only maintain zero resistance until the magnetic field reaches a critical point, where it will be killed,” explained Zach Hadjri, a first-year student in the group. “Instead, this material seems to switch between two superconducting states, like the magnet that starts pointing upwards and can flip downwards when the magnetic field is applied.”
Quantum Mechanics
The secret is how electrons behave at ultra-low temperatures. In conventional superconductors, electrons pair “Cooper pairs” and slide the material without resistance. These pairs usually have zero overall momentum and do not rotate.
But in rhombus graphene, something unusual happens. All electrons collectively occupy the same “valley” – the quantum mechanical momentum state. When these electrons are paired, their combined momentum will not be cancelled.
“You can consider two electrons in a pair of rotations that rotate clockwise or counterclockwise, which corresponds to magnets pointing up or down,” explained Tonghang Han, a fifth-year student in the group. “So we think this is the first observation of a superconductor that manifests itself as a magnet due to the orbital movement of electrons, which is called a chiral superconductor.”
The main findings of the study:
- Materials maintain superconductivity up to 300 mm temperatures
- Displays magnetic hysteresis – Switches between magnetic states, while superconducting
- The critical magnetic field reaches 1.4 Tesla, higher than other graphene superconductors
- Shows strong coupling superconductivity near BCS-BEC crossover
- Prove charge density as low as 2.4×10βcm⁻²
Beyond the headlines
What makes this discovery particularly appealing is that the details are beyond typical coverage: materials operate in a system physicist calls “BCS-BEC crossover”. This represents a boundary region where superconductivity changes from loosely bound Cooper pairs (BCS theory) to tightly bound pairs that behave more like quantum fluids (BEC or Bose-Einstein Condensate).
1.4 Tesla’s high critical magnetic field indicates that these electron pairs are abnormally robust, indicating strongly coupled superconducting bridging fundamental quantum mechanical states. This cross-behavior can unlock new physics that are not suitable for conventional superconductors.
Effect on quantum computing
The discovery has a profound impact on quantum technology. Chiral superconductors are candidates to host major fermions, and these particles can revolutionize quantum computing by making them more tolerant.
“This is a kind,” Han noted. “It is also a candidate for topological superconductors that can enable robust quantum computing.”
Current quantum computers are fragile and lose information when disturbed by environmental noise. If Majorana fermions are present in this material, quantum information can be stored in a way that naturally protects such interference.
“There is really noteworthy for this exotic chiral superconductor,” added Liang Fu, a professor of physics at MIT. The team observed the same behavior in six different samples, confirming the reproducibility of the phenomenon.
Can the next breakthrough in quantum computing come from something as mundane as pencil lead? The discovery of the MIT team suggests that extraordinary physics may be hidden in the most common materials, waiting for the right conditions to reveal itself.
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