Scientists Break 33-Year Ambient-Pressure Superconductivity Record, Map Push Toward Room Temperature

For the first time in more than three decades, scientists have pushed the temperature at which a material becomes superconducting at everyday pressure to a new high—and they have paired the result with an unusually detailed plan for how to go much further.

In a pair of papers published online March 9 in the Proceedings of the National Academy of Sciences (PNAS), researchers report that a mercury-based ceramic known as HgBa₂Ca₂Cu₃O₈+δ reaches a superconducting transition temperature of 151 kelvin (about minus 122°C) at ambient pressure, surpassing a record that has stood since 1993. In the same journal issue, many of the same authors lay out what they call a “programmatic approach” to achieving superconductivity at room temperature and normal atmospheric pressure.

The findings do not bring superconductors into everyday conditions. The new material still has to be cooled far below the freezing point of water, and the evidence so far comes from tiny, fragile samples. But the work breaks a long-standing plateau in the field and signals a shift toward a more coordinated, engineering-style campaign to reach a century-old goal.

What changed: a new ambient-pressure high-water mark

Superconductors conduct electricity with no direct-current resistance and expel magnetic fields, a combination that can enable lossless power lines and powerful magnets. Until now, the highest critical temperature (Tc) at normal pressure was about 133 kelvin in the same mercury-based compound, discovered in 1993 by a team led by physicist Ching‑Wu “Paul” Chu at the University of Houston. That record had not budged despite intense global research.

“The ambient-pressure Tc of 133 K in Hg‑1223 has represented the upper limit for more than 30 years,” the authors of the new experimental paper write, using the shorthand name for the compound. “Here, we report ambient‑pressure 151‑K superconductivity in HgBa₂Ca₂Cu₂O₈+δ stabilized via a pressure‑quench protocol.”

How it works: “freezing in” a high-Tc phase

The experiment centers on pressure quenching. Researchers place a tiny crystal of Hg‑1223 between the tips of two diamonds in a diamond anvil cell, then squeeze it to tens of gigapascals—hundreds of thousands of times atmospheric pressure—while cooling it to about 4 kelvin with liquid helium. Under those extreme conditions, the material adopts a structure that appears to support a higher superconducting temperature.

From that state, the team rapidly releases the pressure back to normal levels, attempting to “freeze in” the high‑Tc phase so it survives at ambient pressure. As the sample warms, they track its electrical resistance.

In multiple runs, the resistance drops sharply around 151 kelvin, significantly above the long-standing 133‑kelvin value. The researchers also report magnetic measurements and X‑ray diffraction data that they say are consistent with a superconducting phase created and stabilized by the pressure‑quench process.

The high‑Tc phase is metastable, meaning it is not the material’s lowest‑energy state but can persist for some time. In press materials, the team said the enhanced superconducting state survived for at least several days when stored in liquid nitrogen at 77 kelvin and, under some conditions, remained detectable even after about two weeks. When stored closer to 200 kelvin, the properties deteriorated more rapidly.

What still needs to be proven

Independent experts say the result is credible and potentially important, while emphasizing that key questions remain.

One limitation is that the paper does not show the resistance dropping all the way to zero, in part because making precise measurements on a microscopic sample under rapidly changing pressure is technically difficult. Superconductivity is defined by exactly zero resistance and by the Meissner effect, in which a material expels magnetic fields.

“The transport data show a strong and sharp drop in resistance, which is suggestive of superconductivity, but the constraints of the diamond anvil cell make it challenging to demonstrate strictly zero resistance,” said one condensed-matter physicist who was not involved in the work and reviewed the figures. “Magnetization and structural data help build the case, but full confirmation will require careful follow‑up and replication.”

The researchers acknowledge those limits and explicitly call for other groups to try to reproduce the result: “Independent verification and further characterization of this metastable phase will be essential,” they write.

If confirmed, the 151‑kelvin temperature would be the highest Tc ever observed at ambient pressure. It remains well below room temperature (about 300 kelvin) and lower than the roughly 200–260 kelvin values reported in hydrogen‑rich compounds under pressures of around 200 gigapascals and higher. Those “hydride superconductors,” realized in diamond anvil cells, are considered unlikely to be practical for power lines or large‑scale devices because sustaining such enormous pressures outside a laboratory is not feasible.

A broader ambition: a roadmap to room-temperature superconductivity

The companion paper in PNAS steps back from the laboratory details to outline a broader strategy. Titled “The path to room‑temperature superconductivity: A programmatic approach,” it is authored by 16 scientists from universities, national laboratories and Intellectual Ventures, a private invention and patent firm based in Bellevue, Washington.

“There are no physical laws preventing this from occurring,” the authors write of room‑temperature superconductivity. “Indeed, superconductivity has been observed in so many different materials under so many different conditions that it is almost a ‘generic’ property of nonmagnetic metals.”

The roadmap identifies two main obstacles:

• The prediction challenge: computational methods and machine‑learning tools can estimate Tc for hypothetical compounds, but many candidates prove unstable or impossible to synthesize.
• The engineering challenge: superconductivity can be tuned by many “knobs”—including pressure, strain, chemical doping, nanoscale layering, optical excitation and electromagnetic cavities—yet researchers cannot reliably predict how combinations of these will affect Tc in a given material.

To address those hurdles, the paper calls for a coordinated effort combining high‑throughput quantum‑mechanical calculations, realistic thermodynamic modeling of synthesis conditions, advanced experimental techniques and data‑driven design. It highlights six particularly promising strategies, including pressure quenching—the same method used in the Hg‑1223 result—alongside building multilayer heterostructures and designing “quantum metamaterials,” where device architecture may matter as much as chemical composition.

Funding, patents and the push to industrialize discovery

The work is funded primarily by the Enterprise Science Fund, a program managed by Intellectual Ventures. Several authors, including lead roadmap author Rohit P. Prasankumar and former Microsoft chief technology officer Nathan Myhrvold, are employees or consultants of the firm. The roadmap paper discloses that the authors and their institutions hold, or have applied for, patents related to high‑temperature superconductors, hydride compounds and superconducting metamaterial devices.

Supporters argue that a more systematic approach is overdue in a field where many major discoveries have been partly serendipitous.

“Superconductivity research has reached a point where isolated breakthroughs are no longer enough,” said Christoph Heil, a theorist at Graz University of Technology in Austria and a co‑author of the roadmap, in a statement released by the university. “We need coordinated campaigns that bring together large‑scale simulations, advanced experiments and machine learning to navigate a vast space of possible materials and structures.”

Others note that the commercial and intellectual property context will likely shape how any eventual technologies are developed and deployed.

Why incremental gains still matter

Superconductors already play roles in MRI machines, particle accelerators and experimental fusion devices, typically using materials that must be cooled with liquid helium or—among so‑called high‑temperature superconductors—with liquid nitrogen. Even incremental increases in Tc at ambient pressure can reduce cooling costs and enable more compact equipment.

Advocates of room‑temperature, ambient‑pressure superconductors say they could eventually reduce power losses in electric grids—estimated in the United States to account for several percent of generated electricity—and enable lighter, more efficient motors and generators for transportation and industry. The roadmap also highlights potential impacts on quantum computing, where many qubits rely on superconducting circuits, and on high‑field magnets that could benefit fusion reactors and scientific instruments.

Specialists caution against expecting rapid change.

“Going from a tiny crystal in a diamond anvil cell to kilometers of wire in a power grid is a massive leap,” said a materials scientist at a U.S. national laboratory who was not authorized to speak on the record. “You have to be able to make the material in bulk, keep the relevant phase stable for years, and engineer it into devices that can survive real‑world conditions. That is a long process even after the basic physics is solidly established.”

The new Hg‑1223 phase, as currently reported, is not yet close to meeting those criteria. Its lifetime appears limited unless kept very cold, and the pressure‑quench process is difficult to control and potentially damaging to the tiny diamonds and electrical leads used. The share of the sample that becomes superconducting has not been fully quantified.

What comes next

Even proponents of the roadmap concede that the path to room‑temperature superconductivity, if it exists, is likely to take decades and involve many more steps. For now, the immediate test will be whether other laboratories can reproduce and refine the new 151‑kelvin result and whether pressure‑quench methods can be generalized to other superconducting families, such as nickelates and iron‑based compounds.

Breaking the 33‑year record does not, by itself, transform power grids or medical scanners. But it marks a measurable move in a field that had seemed stalled at ambient pressure—and sets a clearer framework for what progress might look like in the years ahead, not just as isolated announcements but as part of a deliberate attempt to engineer one of physics’ most elusive states into practical technology.