#superconductivity

AI just supercharged the race to find room temperature superconductors

A new AI-powered search method could dramatically speed the race to discover the room-temperature superconductors that could reshape the future of energy and technology.

Machine learning is giving scientists a powerful new way to search for superconductors, materials that conduct electricity with zero resistance. An international team has demonstrated that AI can rapidly narrow an almost limitless number of possible material combinations to identify the most promising candidates. According to Aalto University Professor Päivi Törmä, who leads the SuperC consortium, the approach could dramatically speed the discovery of new superconductors. Superconductors allow electric current to flow without losing energy, but only when cooled to extremely low temperatures where quantum effects emerge. These remarkable materials are already used in technologies ranging from quantum computers and medical neuroimaging systems to fusion reactors and maglev trains.

For more than 30 years, a record in science held firm: minus 220 degrees Fahrenheit. It defined the highest achieved temperature for any material to become superconducting - able to carry electricity with no resistance - without the need for crushing pressures. In a field known for slow, steady progress, the record had come to seem almost immovable. That limit has always been daunting because most known superconductors work only at temperatures close to absolute zero - hundreds of degrees below zero Fahrenheit. Keeping materials so ultracold requires complex and costly cooling systems. This limits where and how these materials can be applied to niche technologies, like MRI scanners and particle accelerators.

Nickelate superconductors share a common electronic fingerprint

Superconductors, materials that conduct electricity with zero electrical resistance at specific temperature ranges, have proved very promising for the development of quantum computers and other cutting-edge technologies. While most of these materials become superconducting at very low temperatures, others exhibit superconductivity at higher temperatures. Two types of materials that are known to be high-temperature semiconductors are cuprates (i.e., compounds containing negatively charged copper ions) and nickelates (i.e., compounds that contain negatively charged nickel-oxygen ions). While cuprates have been known to be superconductors for decades, nickelates were only recently found to exhibit superconductivity at unusually high temperatures.

Nickelate reveals nodeless gap, providing key clue to high-temperature superconductivity

The mechanism of high-temperature (TC) superconductivity is a key challenge in condensed matter physics. Recently, Chinese scientists made significant progress in the study of high-TC nickelate superconductors. Landmark observations in nickelate films For the first time, scientists observed a nodeless superconducting gap and discovered electron-boson coupling by measuring the electronic structures of Ruddlesden-Popper bilayer nickelate superconducting thin films. These results provide crucial evidence for two fundamental issues in the mechanism of high-TC nickelates: "superconducting gap symmetry" and "superconducting pairing mechanism."

Magnetic fields can 'revive' superconductivity in nickelates, research reveals

A research team led by Professor Denver Li Danfeng, Associate Dean (Research and Postgraduate Education) of the College of Science and Associate Professor in the Department of Physics at City University of Hong Kong (CityUHK), has achieved a significant advance in superconducting materials. Magnetic fields revive superconductivity The team has discovered a magnetic-field-induced "re-entrant superconductivity" phenomenon in infinite-layer nickelate superconductors, in which superconductivity—initially suppressed by a magnetic field—reappears at higher field strengths. This finding challenges the conventional understanding that magnetic fields suppress superconductivity and opens up new directions for exploring unconventional superconducting mechanisms and next-generation superconducting materials.

Observing exotic quasiparticle states in kagome superconductor CsV₃Sb₅

A research team led by Prof. Hao Ning of the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, in collaboration with Anhui University and the University of Science and Technology of China, has identified two distinct types of unusual low-energy quasiparticle states in the kagome superconductor CsV3Sb5 using single-atom impurities as local "quantum probes" combined with scanning tunneling spectroscopy. The study was recently published in Nature Physics. CsV3Sb5 has attracted growing interest for its unusual crystal structure and complex quantum phenomena. Evidence for time-reversal symmetry breaking remains under debate, and the mechanism of its superconductivity is still not fully understood. Studying its response to single-atom impurities provides a promising way to address these questions.

Fragile no more, nickelates get an upgrade that changes how superconductivity endures

Discovered in 2019, the material known as nickelates has intrigued researchers for its potential to become a superconductor at elevated temperatures—a property that could significantly advance such fields as quantum science and energy transmission. However, it's a very unstable material and difficult to work with. But the lab of Professor Charles Ahn has developed a method that could enhance superconductivity in these materials. The results are published in Nature Communications. With their ability to conduct electricity with no resistance, superconductors are a key component to quantum computing, medical imaging, and a number of other fields. A group of copper-oxide compounds known as cuprates have long been central to the study of high-temperature superconductivity ("high temperature" is a relative term—they still need to be kept in very cold environments). Nickelates are especially exciting because they share some of cuprates' key electronic features while offering a new platform for materials design and tuning.