2020/11/30 by Haoxiang Li, H. Li, T. T. Zhang +19 · 42 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Excitation #Phonon #Physics #Physics of Superconductivity and Magnetism #Quantum #Quantum Hall effect #Quantum mechanics #Spin (aerodynamics) #Topological Materials and Phenomena #cond-mat.str-el
paper · pdf · doi:10.1038/s41467-021-23826-1
published in Nature Communications 12(1), 3513 (Nature Portfolio)
openalex publication_date 2021/06/10 · arxiv created 2021/06/15 · arxiv updated 2021/06/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract The Kitaev quantum spin liquid epitomizes an entangled topological state, for which two flavors of fractionalized low-energy excitations are predicted: the itinerant Majorana fermion and the Z 2 gauge flux. It was proposed recently that fingerprints of fractional excitations are encoded in the phonon spectra of Kitaev quantum spin liquids through a novel fractional-excitation-phonon coupling. Here, we detect anomalous phonon effects in α-RuCl 3 using inelastic X-ray scattering with meV resolution. At high temperature, we discover interlaced optical phonons intercepting a transverse acoustic phonon between 3 and 7 meV. Upon decreasing temperature, the optical phonons display a large intensity enhancement near the Kitaev energy, J K ~8 meV, that coincides with a giant acoustic phonon softening near the Z 2 gauge flux energy scale. These phonon anomalies signify the coupling of phonon and Kitaev magnetic excitations in α-RuCl 3 and demonstrates a proof-of-principle method to detect anomalous excitations in topological quantum materials.