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arXiv · 2408.00185

Anharmonic quantum muon effects of light particles in a spin liquid material

Fabian Hotz·Matjaž Gomilšek·Tina Arh·Thomas Hicken·Polona Umek·Andrej Zorko·Hubertus Luetkens
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Abstract

The quantum behavior of light nuclei and other particles in materials challenges classical intuition and introduces novel phenomena. Here we demonstrate that muon spin spectroscopy ( $\mu$SR) is a powerful tool for exploring the quantum effects of light particles, such as the muon, in condensed matter. The muon's quantum nature is profoundly influenced by the surrounding, offering a unique probe for understanding the role of light atoms and their role in shaping local electronic environments. In Zn-barlowite, a candidate quantum spin liquid, we show that standard density functional theory (DFT) methods, which treat the muon as a classical point-like particle, fail to capture its strong quantum anharmonic effects. Only by modeling the muon as a spatially extended quantum particle, thus accounting for the anharmonicity, can the experimental $\mu$SR data be understood. This approach not only improves the interpretation of $\mu$SR results but also opens the door to studying the quantum effects of other light particles, like hydrogen and lithium nuclei, which can greatly influence material properties.

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Fabian Hotz, Matjaž Gomilšek, Tina Arh, Thomas Hicken, Polona Umek, Andrej Zorko, Hubertus Luetkens. 2024-07-31. Anharmonic quantum muon effects of light particles in a spin liquid material. https://arxiv.org/abs/2408.00185

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