Uranium ditelluride is now considered the leading candidate material for a topological superconductor, a key component for advances in quantum computing, after researchers demonstrated it exhibits both required “flavors” of superconductivity. A team led by Brad Ramshaw, associate professor of physics at Cornell University and director of the Laboratory of Atomic and Solid State Physics, redrew uranium ditelluride’s phase diagram, resolving years of uncertainty about its potential.
“No one has yet convincingly demonstrated a topological superconductor, but now we know that uranium ditelluride at least has the right ingredients to make it happen,” Ramshaw said. The research, published in Nature Physics on October 30, also revealed a reversal of the usual pattern where one type of superconductivity is lost as temperature decreases.
Uranium Ditelluride Exhibits Two Distinct Superconductivity Flavors
Uranium ditelluride simultaneously exhibits two distinct types of superconductivity, a characteristic that distinguishes it among the 6,000 superconducting materials catalogued to date. Researchers at Cornell University, led by Brad Ramshaw, redrew the material’s phase diagram, a map charting superconductivity’s emergence with changes in temperature and pressure. This revised diagram resolves longstanding uncertainty about uranium ditelluride’s potential as a topological superconductor, a component important for advancing quantum computing.
Doctoral student Sahas Kamat, the first author of the Nature Physics publication, discovered inconsistencies in previously published research on uranium ditelluride’s behavior under pressure during the investigation. The team’s experiments revealed a unique situation where one type of superconductivity is lost as temperature decreases, a reversal of the usual pattern.
Specifically, they observed one type of superconductivity emerging under regular conditions, extreme cold, while another shows up only in very strong magnetic fields or under squeezing pressure. “We’re trying to find not just different compounds but different types of superconductivity that can be used to do different things,” Ramshaw added. “The important thing about uranium ditelluride is that it can show two different types at the same time.” The parallel search continues for other compounds, but the ability of uranium ditelluride to display both superconductivity types concurrently positions it as the leading candidate.
No one has yet convincingly demonstrated a topological superconductor, but now we know that uranium ditelluride at least has the right ingredients to make it happen.
Brad Ramshaw, associate professor of physics in the College of Arts and Sciences and director of the Laboratory of Atomic and Solid State Physics
Precise Ultrasound Experiments Redraw UTe2’s Phase Diagram
Precise ultrasound experiments revealed an unusual thermodynamic pattern in uranium ditelluride, where one superconducting state diminishes with decreasing temperature, a reversal of typical behavior. The research, detailed in Nature Physics, demonstrates the emergence of one superconductivity type under standard extreme-cold conditions, while the second requires substantial pressure to manifest. The resulting diagram clarifies the potential for both superconductivity “flavors” to combine, resolving longstanding uncertainty about uranium ditelluride’s capacity to host topological superconductivity, though definitive proof remains elusive.
This work extends the group’s broader investigation into novel superconducting materials and their potential applications. Ramshaw added, “There are new superconducting materials being discovered all the time. There have been 6,000 catalogued already, but most of those are basically the same kind of superconductor—they do superconductivity in the same way.”
The map people had in their heads about what the superconductor does as a function of temperature and pressure – it turns out it’s not consistent with thermodynamics.
Sahas Kamat, M.S. ’25
Competing Superconductivities in UTe2 Reveal Unique Temperature Dependence
In experiments redrawing and correcting uranium ditelluride’s phase diagram, researchers in the Ramshaw lab show the potential is there, although not proven yet, for both flavors to mix together to form a topological superconductor, settling years of uncertainty surrounding this much-studied material. “It can happen here because another superconductor comes in and pushes it out of the way,” Ramshaw said, illustrating the dynamic interaction.
This competition, and the resulting phase diagram, clarifies the potential for combining these “flavors” of superconductivity, and suggests uranium ditelluride remains a strong candidate for realizing topological superconductivity. “We’ve established that this is the most likely one we have,” Ramshaw added, reinforcing the material’s position in the search for advanced superconducting materials.
The parallel approach is that nature has at least 6,000 superconductors we’ve found. One of them might be that superconductor.
Brad Ramshaw, associate professor of physics in the College of Arts and Sciences and director of the Laboratory of Atomic and Solid State Physics
See today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals.
