Original version With this story appeared in How much storageme.
In 2024, superconductivity, i.e. the flow of electric current with zero resistance, was discovered in three different materials. Two cases stretch the textbook understanding of the phenomenon. The third one destroys it completely. “This is an extremely unusual form of superconductivity that many people would think was impossible,” he said Ashwin Vishwanatha physicist at Harvard University who was not involved in the discoveries.
Since 1911, when Dutch scientist Heike Kamerlingh Onnes first observed the disappearance of electrical resistance, superconductivity has fascinated physicists. How this happens remains a mystery: the phenomenon requires the pairing of electrons that conduct electricity. Electrons repel each other, so how can they be united?
Then comes the technological promise: superconductivity has already enabled the development of MRI machines and powerful particle colliders. If physicists could fully understand how and when this phenomenon occurs, perhaps they could design a wire that would superconduct electricity under everyday conditions, rather than only at low temperatures, as is currently the case. World-changing technologies may emerge – lossless energy networks, magnetically levitating vehicles.
The recent wave of discoveries has both deepened the mystery of superconductivity and increased optimism. “It seems that when it comes to materials, superconductivity is everywhere,” he said Mateusz Yankowitzphysicist from the University of Washington.
The discoveries come from a recent revolution in materials science: all three recent cases of superconductivity arise in devices composed of flat sheets of atoms. These materials are characterized by unprecedented flexibility; with the press of a button, physicists can switch them between conductive, insulating and more exotic behaviors – a state-of-the-art form of alchemy that has accelerated the search for superconductivity.
It now seems increasingly likely that a variety of causes may be responsible for this phenomenon. Just as birds, bees and dragonflies fly using different wing structures, materials appear to combine electrons in different ways. Even as researchers debate what exactly is happening in the various two-dimensional materials in question, they expect the growing zoo of superconductors will support them get a more universal picture of this tantalizing phenomenon.
Electron pairing
The case of Kamerlingh Onnes’ observations (and superconductivity observed in other extremely frigid metals) was finally solved in 1957. John Bardeen, Leon Cooper and John Robert Schrieffer they figured it out that at low temperatures, the material’s jittery atomic lattice calms down, resulting in more fine effects. The electrons gently attract protons to the lattice, pulling them in, creating an excess positive charge. This distortion, called a phonon, can then attract a second electron, creating a “Cooper pair”. All Cooper pairs can come together into a coherent quantum whole in a way that solitary choices cannot. The resulting quantum soup slides frictionlessly between the material’s atoms, which usually impedes the flow of electricity.
Bardeen, Cooper and Schrieffer’s theory of phonon-based superconductivity won them the 1972 Nobel Prize in Physics. However, it turned out that this was not the whole story. In the 1980s, physicists discovered that copper-filled crystals called cuprates could conduct at higher temperatures, where atomic vibrations washed out phonons. Other similar examples followed.