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 cuts it off completely. “This is a very 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 research.
Since 1911, when Dutch scientist Heike Kamerlingh Onnes first observed the disappearance of electrical resistance, superconductivity has fascinated physicists. How it happens is a pure mystery: the coupling phenomenon requires electrons, which carry an electric current. Electrons repel each other, so how can they come together?
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 this phenomenon occurs, perhaps they can engineer a wire that superconducts electricity under everyday conditions rather than only at low temperatures, as it currently does. World-changing technologies—lossless power grids, magnetically levitated vehicles—may follow.
A recent round of discoveries has deepened the mystery of superconductivity and fueled optimism. “It seems, in materials, superconductivity is everywhere,” said Matthew YankowitzA physicist at the University of Washington.
The findings stem from a recent revolution in materials science: All three new examples of superconductivity arise in devices assembled from flat sheets of atoms. This material exhibits exceptional flexibility; At the touch of a button, physicists can switch them between conducting, insulating, and other exotic behaviors—a modern form of chemistry that supercharged the discovery of superconductivity.
It now seems increasingly likely that a variety of causes may give rise to the phenomenon. Just as birds, bees and dragonflies all fly using different wing structures, materials seem to bind electrons in different ways. Even as researchers debate what’s going on in the various two-dimensional materials in question, they anticipate that the growing zoo of superconductors will help them gain a more comprehensive view of the fascinating phenomenon. .
Pairing electrons
The case for Kammerling’s observations (and superconductivity seen in other very cold metals) finally broke in 1957. John Bardeen, Leon Cooper, and John Robert Schreifer. found out That at lower temperatures, the turbulent atomic lattice of a material relaxes, so more critical effects occur. The electrons slowly attract the protons in the lattice, pulling them inward to create an additional positive charge. That distortion, known as a phonon, can then pull in another electron, creating a “Cooper pair”. Cooper pairs can all combine into a coherent quantum entity in a way that single selections cannot. The resulting quantum soup slides between the material’s atoms without friction, which would normally prevent the flow of electricity.
Bardeen, Cooper, and Schreifer’s theory of phonon-based superconductivity won them the Nobel Prize in Physics in 1972. But this is not the whole story. In the 1980s, physicists discovered that copper-filled crystals called cuprates could superconduct at high temperatures, where the atoms jiggled the phones. Other similar examples followed.
