Professor and Interim Chair Lu Li

As someone who studies materials, Lu Li knows people want to hear about the exciting new applications and technologies his discoveries could enable. Sometimes, though, what he finds is just too weird or extreme to have any immediate use.

Working with an international team of researchers, Li has made one of those latter types of discoveries, which the group detailed in the journal Physical Review Letters.

“I would love to claim that there’s a great application, but my work keeps pushing that dream further away,” said Li, professor of physics at the University of Michigan. “But what we’ve found is still really bizarre and exciting.”

The discovery was supported, in part, by the U.S. National Science Foundation and the U.S. Department of Energy and pertains to what are called quantum oscillations. These oscillations are found in metals and can be thought of as a phenomenon in which the metal’s electrons act like springs, Li said. By applying a magnetic field, researchers can change the speed with which those electron springs wiggle.

But, over the past several years, researchers have discovered the same quantum oscillations in insulators—nonmetals that don’t typically conduct heat or electricity. This led to a question that has stymied the field: Are those oscillations originating at only the surface of the material or is the behavior something that comes from within the material’s bulk?

From the standpoint of applications, the surface would be the more enthralling answer. Scientists are already exploring materials called topological insulators, which demonstrate metal-like behaviors at their surfaces while maintaining an insulator identity in their bulk, to enable new electronic, optical and quantum technologies.

But working with the world’s largest and most powerful magnet lab in the world, the National Magnetic Field Laboratory, Li and his colleagues have provided evidence that the quantum oscillations arise from the bulk.

“I wish I knew what to do with that, but at this stage we have no idea,” Li said. “What we have right now is experimental evidence of a remarkable phenomenon, we’ve recorded it and, hopefully, at some point, we’ll realize how to use it.”

The team included more than a dozen collaborators from six institutions in the U.S. and Japan. In addition to Li, the team included research fellow Kuan-Wen Chen and graduate students Yuan Zhu, Guoxin Zheng, Dechen Zhang, Aaron Chan and Kaila Jenkins from U-M.

Please read the rest of the story at the Michigan News website.

More Information:
Professor and Interim Chair Lu Li

Study: Quantum Oscillations in the Heat Capacity of Kondo Insulator YbB12 (DOI: 10.1103/ms3x-pjsk)