Professor Paul Ching-Wu Chu holds a diamond anvil cell (DAC) in a 91视频 lab. The DAC was used to help the UH team break the temperature record for superconductivity at ambient pressure.
Key Takeaways
- Researchers at the 91视频 and its Texas Center for Superconductivity set a new ambient-pressure superconductivity record of 151 K, the highest transition temperature achieved without maintaining high pressure since superconductivity was first discovered in 1911.
- The breakthrough uses a 鈥減ressure quenching鈥� technique that locks in enhanced superconducting properties after pressure is removed, allowing the material to remain stable under normal conditions.
- The advance moves researchers closer to the goal of room-temperature superconductivity, which could dramatically improve power grids, medical technologies and energy systems by enabling electricity to flow without resistance.
Researchers from the Texas Center for Superconductivity (TcSUH) and the department of physics at the 91视频 have broken the temperature record for superconductivity at ambient pressure 鈥� a breakthrough that could eventually lead to more efficient ways to generate, transmit and store energy.
The UH team achieved a transition temperature (Tc) of 151 Kelvin (about minus 122 degrees Celsius) under ambient pressure 鈥� the highest ever recorded for all the reported superconductors at ambient pressure since the discovery of superconductivity in 1911. The transition temperature is the point below which a material becomes superconducting, meaning electricity can flow through it without resistance.
Raising this temperature has been a major goal in superconductivity research for decades. The closer scientists can push the Tc toward room temperature, the more practical and affordable superconducting technologies could become.
The research by UH physicists Ching-Wu Chu and Liangzi Deng was in the Proceedings of the National Academy of Sciences. The work was funded by , a global invention and investment company, the state of Texas via TcSUH and other foundations.
鈥淭ransmitting electricity in the grid loses about 8% of the electricity,鈥� said Chu, professor of physics, TcSUH founding director and the paper鈥檚 senior author. 鈥淚f we conserve that energy, that鈥檚 billions of dollars of savings and it also saves us lots of effort and reduces environmental impacts.鈥�
Superconductors allow electricity to flow without resistance, which makes them useful for improving electrical grids, building advanced medical imaging systems, enabling fusion energy technologies and developing faster electronics. However, most superconductors must be cooled to extremely low temperatures, which makes them expensive and difficult to use.
鈥淥nce we bring the material to ambient pressure, it becomes much more accessible for scientists to use well-developed instrumentation to investigate it and further develop technologies for ambient condition operations,鈥� said Deng, assistant professor of physics, principal investigator at the TcSUH and lead author of the paper.
From left: Paul Ching-Wu Chu and Liangzi Deng developed a pressure-quench protocol to stabilize high-pressure metastable phases at ambient pressure. These are the instruments used to validate high temperature superconductivity results at record ambient pressure.
Breaking the Temperature Barrier
For more than a half century, scientists made steady progress in their search for new kinds of superconducting materials with higher Tc. A groundbreaking 1987 discovery by Chu and colleagues found a material called YBCO reaches superconductivity at minus 180 degrees C, or 93 K, ushering in the worldwide race to develop high-temperature superconductors.
Subsequently, a mercury-based, copper-oxide ceramic, known as Hg1223, that superconducts at up to minus 140 degrees C, or 133 K, was discovered in 1993 and held the ambient pressure record Tc until now.
The UH team increased it by 18 degrees C to reach 151 K.
鈥淥nce we bring the material to ambient pressure, it becomes much more accessible for scientists to use well-developed instrumentation to investigate it and further develop technologies for ambient condition operations.鈥�
鈥擫iangzi Deng, lead author of the paper
This advance was made possible through a technique known as pressure quenching 鈥� a new approach for superconductors, though commonly used in other areas such as creating diamonds. In this method, researchers first apply intense pressure to the material to enhance its superconducting properties and raise its transition temperature.
While the material is under pressure, it is cooled to a specific temperature and rapidly released from pressure completely, effectively 鈥渓ocking in鈥� the enhanced superconducting properties. Using this method, the researchers were able to preserve the higher Tc even after the pressure was removed, allowing the material to remain stable under normal conditions.
鈥淥ther researchers have shown that reaching superconductivity at room temperature under pressure is achievable,鈥� Chu said. 鈥淥ur method shows that it is possible to retain that state without maintaining pressure.鈥�
Pushing the Research Forward
Although ambient-pressure room-temperature superconductivity 鈥� around 300 K 鈥� remains the ultimate goal, researchers said the new record represents an important step forward and is significant in the world of superconductivity.
鈥淭his finding has great potential,鈥� Chu said. 鈥淲e believe, with enough people working on it and given enough time, we should be able to realize the potential.鈥�
Chu and Deng are also co-authors on a companion perspective paper from the study鈥檚 main funder, Intellectual Ventures. The complementary paper, also , outlines six different methods for tuning or transforming materials to reach higher-temperature superconductivity, one being pressure quenching, said Rohit Prasankumar, director of superconductivity research at Intellectual Ventures.
鈥淩oom-temperature superconductivity has been seen as a 鈥榟oly grail鈥� by scientists for over a century,鈥� Prasankumar said. 鈥淭he UH team鈥檚 result shows that this goal is closer than ever before. However, the distance between the new record set in this study and room temperature is still about 140 degrees C. Closing this gap will require concerted, intentional efforts by the broader scientific community, including materials scientists, chemists, and engineers, as well as physicists.鈥�