original version Of this story appeared in Quanta MagazineE,
In 2024, superconductivity – the flow of electric current with zero resistance – was discovered in three different materials. Two examples enhance the textbook understanding of the phenomenon. The third blows it completely to pieces. “This is an extremely unusual form of superconductivity that many people would have said was not possible,” said Ashwin VishwanathA physicist at Harvard University who was not involved in the discoveries.
Superconductivity has fascinated physicists since 1911, when Dutch scientist Heike Kamerlingh Onnes first observed the disappearance of electrical resistance. How this happens is a pure mystery: the phenomenon requires electrons to pair together, which carry electric current. Electrons repel each other, so how can they unite?
Then there's the technological promise: Already, superconductivity has enabled the development of MRI machines and powerful particle colliders. If physicists can fully understand how and when the phenomenon arises, perhaps they can create a wire that superconducts electricity under everyday conditions, not just at particularly low temperatures, as Happens in the present. World-changing technologies—lossless power grids, magnetically flying vehicles—could follow.
Recent discoveries have complicated the mystery of superconductivity and increased optimism. “It appears that, in materials, superconductivity is everywhere,” said Matthew YankowitzA physicist at the University of Washington.
These discoveries stem from a recent revolution in materials science: All three new examples of superconductivity arise in devices assembled from flat sheets of atoms. These materials exhibit unprecedented flexibility; At the touch of a button, physicists can switch them between conduction, insulation and more exotic behaviors – a modern form of alchemy that has supercharged the discovery of superconductivity.
There is now an increasing possibility that a variety of factors may give rise to this phenomenon. Just as birds, bees and dragonflies all fly using different wing structures, the material also appears to bind electrons together in different ways. Even though researchers are debating what exactly is happening in various two-dimensional materials, they anticipate that the growing zoo of superconductors will help them get a more universal view of the fascinating phenomenon.
pairing of electrons
The matter of the Kammerling Ones observation (and superconductivity observed in other ultracold metals) was finally resolved in 1957. John Bardeen, Leon Cooper, and John Robert Schriefer Figured out That at lower temperatures, the jittered atomic lattice of a substance relaxes, so more delicate effects emerge. The electrons gently tug on the protons in the lattice, pulling them inward, creating an additional positive charge. That distortion, known as a phonon, can then pull out a second electron and form a “Cooper pair.” Cooper pairs can all come together into a coherent quantum entity in a way that singletons cannot. The resulting quantum soup slides frictionlessly between the material's atoms, which would normally disrupt electrical flow.
Bardeen, Cooper, and Schriefer's theory of phonon-based superconductivity won them the Physics Nobel Prize in 1972. But this did not turn out to be the whole story. In the 1980s, physicists discovered that copper-filled crystals called cuprates could be superconductors at high temperatures, where atomic jiggles wash out phonons. Other similar examples followed.