Observation of Unconventional Charge Density Wave without Acoustic Phonon Anomaly in Kagome Superconductors AV3Sb5 ( A=Rb , Cs)
By Haoxiang Li, T. T. Zhang, T. Yilmaz, Y. Pai, C. Marvinney, A. Said, Q. Yin, C. Gong, Z. Tu, E. Vescovo and 7 more. Physical Review X, 2021
258 citations recorded by the source corpus.
The combination of nontrivial band topology and symmetry-breaking phases gives rise to novel quantum states and phenomena such as topological superconductivity, quantum anomalous Hall effect, and axion electrodynamics. Evidence of intertwined charge density wave (CDW) and superconducting order parameters has recently been observed in a novel kagome material AV(3)Sb(5) (A = K, Rb, Cs) that features a Z(2) topological invariant in the electronic structure. However, the origin of the CDW and its intricate interplay with the topological state has yet to be determined. Here, using hard-x-ray scattering, we demonstrate a three-dimensional CDW with 2 x 2 x 2 superstructure in (Rb, Cs)V3Sb5. Unexpectedly, we find that the CDW fails to induce acoustic phonon anomalies at the CDW wave vector but yields a novel Raman mode that quickly damps into a broad continuum below the CDW transition temperature. Our observations exclude strong electron-phonon-coupling-driven CDW in AV(3)Sb(5) and support an unconventional CDW that was proposed in the kagome lattice at van Hove filling.
Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry, Physical and Theoretical Chemistry
View Paper: https://www.semanticscholar.org/paper/57220009ed702d6e7e8602e857a6efa157cf5b87
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In Atomic and Molecular Physics, and Optics
In Materials Chemistry
Citations in the corpus
- Quantum states and intertwining phases in kagome materials (2023, background): “In addition, the results of hard X-ray scattering experiments with (Cs, Rb)V 3 Sb 5 indicate the absence of soft phonon modes, suggesting weak electron–phonon coupling 136 .”