Physicists at ISTA Explain Baffling Reentrant Superconductivity in Strange Quantum Material Using Novel High-Field Measurement Technique

New measurement technique from ISTA identifies magnetic fluctuations as the cause for reentrant superconductivity in the quantum material UTe2.

By: AXL Media

Published: Apr 30, 2026, 8:13 AM EDT

Source: Information for this report was sourced from EurekAlert!

Challenging the Scientific Textbooks on Quantum Material Behavior

The discovery of uranium ditelluride, or UTe2, in 2019 introduced a significant puzzle to the field of condensed matter physics. Unlike conventional superconductors that lose their zero-resistance state when exposed to magnetic fields, UTe2 exhibits a phenomenon known as reentrant superconductivity. This means the material loses its superconducting properties at a lower magnetic field, approximately 10 Tesla, only to have them reappear at extreme fields between 40 and 70 Tesla. Assistant Professor Kimberly Modic from the Institute of Science and Technology Austria notes that while scientists have uncovered many mysteries in UTe2, her team has finally presented evidence for the mechanism driving this nearly impossible behavior.

The Search for Magnetic Glue in Non-Magnetic Superconductors

In traditional superconductors, the pairing of electrons that allows for zero electrical resistance is caused by vibrations in the material's structure. Unconventional superconductors usually rely on a magnetic mechanism, often being magnets themselves. However, UTe2 is not magnetic, making its ability to reach a special superconducting state particularly confusing for researchers. To investigate, PhD student Valeska Zambra led the development of a technique to probe the material just before it enters the high-field superconducting phase. The goal was to see if magnetic fluctuations could explain the "reentrant" state that only appears under temperatures colder than outer space.

Developing the Cantilever Shaking Method for Extreme Environments

To study UTe2 under extreme magnetism, the ISTA team utilized pulsed field facilities where magnetic fields increase to 60 Tesla and back within a tenth of a second. Because the window of time is so short, the researchers had to devise a way to interrogate the sample rapidly. They placed a tiny specimen, roughly the thickness of a human hair, onto a cantilever—a thin stick that allows them to shake the sample in the field. This controlled "wiggle" makes the direction of the magnetic field appear to oscillate from the crystal's perspective, enabling the measurement of transverse magnetic susceptibility, a property previously inaccessible under such extreme conditions.