Cornell researchers have found that uranium ditelluride can support two types of superconductivity at the same time, a result that strengthens its promise for quantum-computing research without proving it is the long-sought material researchers hope to find.
The experiments mapped how the material behaves under extreme cold, pressure and magnetic fields, Cornell reported. The work appeared Oct. 30 in Nature Physics.
Two states meet under extreme conditions
One superconducting state emerges when the material is cooled. A different state can appear under strong magnetic fields or pressure. The researchers found a region where the two coexist and interact.
Brad Ramshaw, associate professor of physics and director of Cornell’s Laboratory of Atomic and Solid State Physics, is the corresponding author. Doctoral student Sahas Kamat is the first author.
Their paper, “Thermodynamic Discovery of Tetracriticality and Emergent Multicomponent Superconductivity in UTe2,” addresses a problem with earlier maps of the material’s phases. Kamat said those maps did not fit established thermodynamic rules.
The group used pulse-echo ultrasound to measure changes in the material and reconstruct its phase boundaries. The authors’ publicly available manuscript describes evidence for an additional transition and a region containing both superconducting components.
Cooling can push one state out
The experiment also showed an unusual effect: One component disappeared as the temperature fell further, because the competing superconducting state pushed it out.
The work involved temperatures between 1 and 2 kelvin, close to absolute zero, and extreme pressure. Kamat likened the force concentrated on the small sample to nine cars balanced on a pinky.
The finding is important because different superconducting states are defined by the behavior of paired electrons. Finding two states in one material creates a possible route toward a topological superconductor, which could be useful in quantum computing.
A possible application remains several steps away
Ramshaw emphasized that the ingredients are present, but the experiments have not established topological superconductivity or a working quantum-computing application.
Researchers from the University of Maryland, Karlsruhe Institute of Technology and Canadian Institute for Advanced Research also contributed. Support came from the U.S. Department of Energy, Gordon and Betty Moore Foundation, NIST Center for Neutron Research, Maryland Quantum Materials Center, German Research Foundation and Simons Foundation.
FingerLakes1.com is the region’s leading all-digital news publication. The company was founded in 1998 and has been keeping residents informed for more than two decades. Have a lead? Send it to news@fingerlakes1.com.
