Original version belong to this story appeared in How much is the magazine?e.
In 2024, superconductors—electric current with zero resistance—were discovered in three separate materials. Two cases expand textbook understanding of this phenomenon. The third one shreds it completely. “It's an extremely unusual form of superconductivity that many people would say is impossible,” he said. Ashwin Vishwanatha physicist at Harvard University who was not involved in these discoveries.
Since 1911, when Dutch scientist Heike Kamerlingh Onnes first saw resistance disappear, superconductivity has fascinated physicists. There's a pure mystery to how it happens: The phenomenon requires electrons, carrying electric current, to combine with each other. Electrons repel each other, so how can they fuse?
Then there's the technological promise: Superconductivity has enabled the development of powerful MRI machines and particle colliders. If physicists can fully understand how and when this phenomenon arises, perhaps they can make a superconducting wire under everyday conditions rather than just at low temperatures as is currently the case. now. World-changing technologies – lossless power grids, magnetically powered vehicles – may follow.
A series of recent discoveries has both added to the mystery of superconductivity and increased optimism. “It seems that, in materials, superconductors are everywhere,” said Matthew Yankowitza physicist at the University of Washington.
These discoveries stem from a recent revolution in materials science: All three new cases of superconductivity appeared in devices assembled from flat atomic sheets. These materials demonstrate unprecedented versatility; At the touch of a button, physicists can switch them between conductive, insulating, and more exotic behaviors—a form of modern alchemy that has fueled the hunt for superconductors.
Nowadays it seems that there are more and more different causes that can give rise to this phenomenon. Just as birds, bees and dragonflies all fly using different wing structures, the materials appear to couple electrons together in different ways. Even as researchers debate exactly what is happening in the different two-dimensional materials in question, they predict that an increasing number of superconductors will help them achieve a universal view. more about this fascinating phenomenon.
Electron pairing
The case for Kamerlingh Onnes's observations (and the superconductivity seen in other extremely cold metals) was finally broken in 1957. John Bardeen, Leon Cooper and John Robert Schrieffer have found that at low temperatures, the material's vibrating atomic lattice subsides, so more subtle effects appear. The electrons gently pull on the protons in the lattice, drawing them in to create an excess of positive charge. That distortion, called a phonon, can then attract a second electron, forming a “Cooper pair.” All 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 impedes the flow of electricity.
Bardeen, Cooper and Schrieffer's phonon-based theory of superconductivity earned them the Nobel Prize in physics in 1972. But it turns out that's not the whole story. In the 1980s, physicists discovered that copper-filled crystals called cuprates could superconduct at higher temperatures, where atomic vibrations wash out phonons. Other similar examples follow.