This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Quantum researchers are searching for a topological superconductor—a material that, if discovered, would allow major advances in quantum computing by combining two distinct "flavors" of superconductivity. This material remains elusive, but Cornell researchers have demonstrated that uranium ditelluride can exhibit both flavors at once, setting it apart 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," said Brad Ramshaw, associate professor of physics in the College of Arts and Sciences and director of the Laboratory of Atomic and Solid State Physics. "Thermodynamic Discovery of Tetracriticality and Emergent Multicomponent Superconductivity in UTe2" was published in Nature Physics on Oct. 30 with Ramshaw as the corresponding author. Doctoral student Sahas Kamat, M.S. '25, is the first author.
In uranium ditelluride, one type of superconductivity emerges under regular conditions: extreme cold. Another shows up only in very strong magnetic fields or under squeezing pressure. In experiments redrawing and correcting uranium ditelluride's phase diagram—the map of where superconductivity emerges as a function of temperature and pressure or a magnetic field—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.
The lab's precise pulse ultrasound experiments also measured a unique situation where one type of superconductivity is lost as temperature decreases, a reversal of the usual pattern. The work stems from the Ramshaw group's main focus: looking for new types of superconductors. "We're trying to find not just different compounds but different types of superconductivity that can be used to do different things," he said.
"There are new superconducting materials being discovered all the time. There have been 6,000 cataloged already. But most of those are basically the same kind of superconductor—they do superconductivity in the same way." Roughly speaking, electrons in a superconductor can orbit each other, Ramshaw said; different types—or "flavors"—of superconductivity are defined by the amount and orientation of angular momentum that two electrons have when paired together in a superconducting state.
There are other compounds that can show more than one type of superconductivity, Ramshaw said. For instance, one rare heavy-fermion superconductor changes what type it is as a function of magnetic field. "The important thing about uranium ditelluride is that it can show two different types at the same time," he said.
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