New superconducting materials have just been discovered

The original version of this story appeared in How many magazinese.

In 2024, superconductivity—the flow of electric current with zero resistance—was discovered in three different materials. Two examples extend the understanding of the phenomenon in the textbook. The third breaks it down completely. “This is an extremely unusual form of superconductivity that many people say is impossible,” he said. Ashwin Vishwanathphysicist 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. There is a secret to how this happens: This phenomenon requires the pairing of electrons that carry an electric current. Electrons repel each other, so how can they come together?

Then there’s the technological promise: Superconductivity has already enabled the development of MRI machines and powerful particle colliders. If physicists can fully understand how and when this phenomenon occurs, they may be able to develop a wire that transmits electricity in everyday conditions, not just at low temperatures as it does today. World-changing technologies—lossless power grids, magnetically powered vehicles—may follow.

A number of recent discoveries both add to the mystery of superconductivity and fuel optimism. “Superconductivity in materials seems to be everywhere,” he said Matthew Jankowitzin physics at the University of Washington.

The discoveries stem from a recent revolution in materials science: All three new examples of superconductivity arise in devices assembled from flat layers of atoms. These materials exhibit unprecedented flexibility; with the touch of a button, physicists can switch them between conducting, insulating and more exotic behaviors—a form of modern alchemy fueling the hunt for superconductivity.

Now it is increasingly likely that various reasons can cause the phenomenon. Just as birds, bees, and dragonflies fly using different wing structures, materials pair electrons in different ways. Even as researchers debate exactly what’s going on in the various two-dimensional materials in question, they expect the growing zoo of superconductors to help them gain a more universal picture of the fascinating phenomenon.

Pairing of electrons

Kamerling Onnes’s observations (and the superconductivity seen in other extremely cold metals) finally cracked the case in 1957. John Bardin, Leon Cooper, and John Robert Schrieffer understood at lower temperatures, the material’s vibrating atomic network quiets down, so subtler effects emerge. The electrons gently pull on the protons in the cage and pull them in to create an excess positive charge. This deformation, known as a phonon, can then attract a second electron to form a ‘Cooper pair’. Cooper pairs can combine into a coherent quantum entity in a way that single elections cannot. The resulting quantum soup slides frictionlessly between the atoms of the material, which normally prevents the flow of electricity.

Bardin, Cooper and Schrieffer’s theory of phonon-based superconductivity won them the 1972 Nobel Prize in Physics. But it turned out that this was not the whole story. In the 1980s, physicists discovered that copper-filled crystals called cuprates could become superconductors at higher temperatures, where atomic vibrations wash out phonons. Other similar examples follow.