Researchers Uncover Bizarre Quantum Oscillations Defying Physics

A groundbreaking discovery from researchers at the University of Michigan has revealed unexpected quantum oscillations within an insulating material, challenging established principles of physics. This remarkable finding, detailed in the journal Physical Review Letters, indicates that these oscillations stem from the material’s bulk rather than its surface, suggesting a new duality in material science where substances can act as both metals and insulators.

The study, conducted at the National Magnetic Field Laboratory, involved an international team of scientists, including physicist Lu Li, who leads research on advanced materials. The project was supported by the U.S. National Science Foundation and the U.S. Department of Energy. Li emphasized the unusual nature of their findings, stating, “What we’ve found is still really bizarre and exciting.”

Exploring Quantum Oscillations

The research delves into quantum oscillations, a phenomenon typically observed in metals where electrons behave like tiny springs that respond to magnetic fields. By altering the strength of the magnetic field, scientists can influence the vibrational patterns of these “electron springs.” However, recent discoveries have identified similar oscillations in insulators—materials expected to be non-conductive. This revelation sparked debate regarding whether these oscillations originate from the material’s surface or its bulk.

To investigate this phenomenon, Li and his colleagues utilized the powerful magnets at the National Magnetic Field Laboratory. Their experiments provided conclusive evidence that the oscillations arise from the material’s bulk. Li remarked, “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.”

A Collaborative Effort

The study brought together over a dozen scientists from six institutions across the United States and Japan. Kuan-Wen Chen, a research fellow involved in the project, highlighted the significance of their findings: “For years, scientists have pursued the answer to a fundamental question about the carrier origin in this exotic insulator: Is it from the bulk or the surface, intrinsic or extrinsic? We are excited to provide clear evidence that it is bulk and intrinsic.”

Li describes the discovery as part of a “new duality” in materials science, similar to the historical realization that light and matter can exhibit both wave and particle characteristics. This new understanding suggests that certain materials can operate as both conductors and insulators. The team focused on a compound known as ytterbium boride (YbB12), investigating its behavior under extreme magnetic conditions exceeding 35 Tesla—approximately 35 times stronger than the magnetic field inside a hospital MRI machine.

Li explained the implications of their findings, stating, “Effectively, we’re showing that this naive picture where we envisioned a surface with good conduction that’s feasible to use in electronics is completely wrong. It’s the whole compound that behaves like a metal even though it’s an insulator.”

The research has opened up new avenues for exploration at the quantum level, raising further questions about the behavior of materials. Yuan Zhu, a graduate student involved in the study, expressed excitement over the confirmation of bulk oscillations, stating, “We don’t yet know what kind of neutral particles are responsible for the observation. We hope our findings motivate further experiments and theoretical work.”

This project also received additional support from the Institute for Complex Adaptive Matter, the Gordon and Betty Moore Foundation, the Japan Society for the Promotion of Science, and the Japan Science and Technology Agency. As researchers continue to unravel the complexities of quantum materials, their findings promise to reshape our understanding of physics and material science for years to come.