New quantum state of matter found at interface of exotic materials

Summary

Crystal structure and temperature dependence of resistivity of EIO/DTO. Credit: Science Advances (2025). DOI: 10.1126/sciadv.adr6202 Scientists have discovered a new way that matter can exist—one that is different from the usual states of solid, liquid, gas or plasma—at the interface of two exotic materials made into a sandwich. The new quantum state, called quantum liquid crystal, appears to follow its own rules and offers characteristics that could pave the way for advanced technological applications, the scientists said. In an article published in the journal Science Advances, a Rutgers-led team of researchers described an experiment that focused on the interaction between a conducting material called the Weyl semimetal and an insulating magnetic material known as spin ice when both are subjected to an extremely high magnetic field. Both materials individually are known for their unique and complex properties. "Although each material has been extensively studied, their interaction at this boundary has remained entirely unexplored," said Tsung-Chi Wu, who earned his doctoral degree in June from the Rutgers graduate program in physics and astronomy and is the first author of the study. "We observed new quantum phases that emerge only when these two materials interact. This creates a new quantum topological state of matter at high magnetic fields, which was previously unknown." The team discovered that at the interface of these two materials, the electronic properties of the Weyl semimetal are influenced by the magnetic properties of the spin ice. This interaction leads to a very rare phenomenon called "electronic anisotropy" where the material conducts electricity differently in different directions. Within a circle of 360 degrees, the conductivity is lowest at six specific directions, they found. Surprisingly, when the magnetic field is increased, the electrons suddenly start flowing in two opposite directions. This discovery is consistent with a characteristic se...