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arXiv · 2209.13342

Order-disorder Peierls instability in the kagome metal (Cs,Rb)V$_3$Sb$_5$

D. Subires·A. Korshunov·A. H. Said·L. Sánchez·Brenden R. Ortiz·Stephen D. Wilson·A. Bosak·S. Blanco-Canosa
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Abstract

The nature of the charge density wave phases in the kagome metal compound AV$_3$Sb$_5$ has raised many questions and their origin is still under debate. Here, we combine diffuse scattering (DS) and inelastic x-ray scattering (IXS) to identify a 3-dimensional (3D) precursor of the charge order with propagation vector (0.5 0 0.5), which condenses into a 3D-CDW through a first order phase transition. The quasi-elastic critical scattering indicates that the dominant contribution to the diffuse precursor is the elastic central peak without phonon softening. However, the inelastic spectra show a small broadening of the Einstein-type phonon mode on approaching the phase transition. Our results point to the situation where the Fermi surface instability at the \textit{L} point is of order-disorder type with a critical growth of quasi-static domains. The results go beyond the classical weak-coupling Peierls transition dynamics and are discussed within models including strong-electron phonon coupling and non-adiabaticity.

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D. Subires, A. Korshunov, A. H. Said, L. Sánchez, Brenden R. Ortiz, Stephen D. Wilson, A. Bosak, S. Blanco-Canosa. 2022-09-27. Order-disorder Peierls instability in the kagome metal (Cs,Rb)V$_3$Sb$_5$. https://doi.org/10.1038/s41467-023-36668-w

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