University of Houston Physicists Achieve Highest Ambient-Pressure Superconducting Transition Temperature

Researchers at the University of Houston and its Texas Center for Superconductivity have established a new record for superconductivity at ambient pressure, achieving a transition temperature of 151 Kelvin, approximately minus 122 degrees Celsius, the highest ever recorded under normal conditions since the phenomenon was first discovered in 1911. This breakthrough utilizes a “pressure quenching” technique to stabilize enhanced superconducting properties even after pressure is removed, a step toward making the technology more accessible for widespread application. The advance brings scientists closer to the long-sought goal of room-temperature superconductivity, potentially revolutionizing power grids, medical technologies, and energy systems by eliminating electrical resistance. “Transmitting electricity in the grid loses about 8% of the electricity,” said Ching-Wu Chu, professor of physics and founding director of the TcSUH; “If we conserve that energy, that’s billions of dollars of savings and it also saves us lots of effort and reduces environmental impacts.”

151K Ambient Pressure Superconductivity Record Established by UH Team

This accomplishment bypasses a longstanding limitation in the field, as most superconducting materials require costly and complex cryogenic cooling to function, hindering widespread application. The team’s success hinges on a novel “pressure quenching” technique, initially employed in diamond creation, that effectively traps enhanced superconducting properties within the material even after pressure is released. The process involves applying intense pressure to the material, cooling it, and then rapidly removing the pressure, locking in the improved characteristics. “Once 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,” explained Liangzi Deng, assistant professor of physics and lead author of the study published March 9 in the Proceedings of the National Academy of Sciences. This advance builds upon earlier breakthroughs, including the 1987 discovery of YBCO superconductivity at 93 K and the 1993 record of 133 K held by a mercury-based ceramic.

Pressure Quenching Stabilizes High-Temperature Superconducting Properties

This accomplishment represents a significant leap forward in the field, as it demonstrates a pathway toward superconducting materials that function at more accessible temperatures. Central to this breakthrough is a technique called “pressure quenching,” borrowed from materials science and newly applied to superconductivity. The process initially involves subjecting the material to intense pressure to elevate its superconducting properties and transition temperature. Crucially, the team doesn’t maintain this pressure indefinitely; instead, they rapidly release it while the material is cooled, effectively locking in the enhanced characteristics. This stabilization is vital because it allows for easier investigation and potential application of the material without the constraints of high-pressure environments. Professor Paul Ching-Wu Chu, founding director of the TcSUH and senior author of the paper, noted that while room-temperature superconductivity, around 300 Kelvin, remains the ultimate objective, this new record demonstrates that retaining enhanced superconducting states without constant pressure is indeed possible. “Other researchers have shown that reaching superconductivity at room temperature under pressure is achievable,” Chu said. “Our method shows that it is possible to retain that state without maintaining pressure.”

YBCO and Hg1223 Preceded UH’s New Transition Temperature

The University of Houston team’s recent achievement in superconductivity didn’t emerge in isolation; rather, it builds upon decades of incremental progress in materials science, following earlier breakthroughs with YBCO and Hg1223. A pivotal moment arrived in 1987 when Professor Ching-Wu Chu, also leading the current research, and his colleagues discovered that YBCO achieved superconductivity at minus 180 degrees Celsius, or 93 Kelvin, initiating a global pursuit of higher-temperature superconductors. This discovery, while significant, was later surpassed in 1993 by the identification of a mercury-based, copper-oxide ceramic known as Hg1223, which exhibited superconductivity at up to minus 140 degrees Celsius, or 133 Kelvin, and held the ambient pressure record until now. The UH team’s work increased this temperature by 18 degrees Celsius, reaching 151 Kelvin, a substantial leap forward.

This advance was made possible through a technique known as pressure quenching, commonly used in other areas such as creating diamonds. Researchers first apply intense pressure to the material to enhance its superconducting properties and raise its transition temperature. Rohit Prasankumar, director of superconductivity research at Intellectual Ventures, noted that “Room-temperature superconductivity has been seen as a ‘holy grail’ by scientists for over a century,” and the UH team’s result indicates that this goal is increasingly attainable.

The pursuit of room-temperature superconductivity gained momentum as Intellectual Ventures detailed multiple avenues for achieving this long-sought goal, building on recent advances at the University of Houston. One key method highlighted is “pressure quenching,” the technique used by the UH team to stabilize high-temperature superconductivity at normal atmospheric conditions. This process, though established in materials science, is newly applied to superconductivity research, allowing for easier material investigation and potential technological development.