Persistence of charge density wave fluctuations in the absence of long-range order in a hole-doped kagome metal

Abstract

The kagome metals $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs) exhibit a complex interplay between charge density wave (CDW) order and superconductivity. In this study, we use ultrafast coherent phonon spectroscopy to probe the evolution of CDW order in hole-doped CsV${}_3$Sb${}_{5-x}$Sn${}_x$ across a broad range of compositions ($0\le x\le 0.68$). While thermodynamic and diffraction measurements show long-range CDW order vanishes above $x\approx 0.05$, we observe persistent signatures of CDW fluctuations up to the highest doping levels, with correlation times on the order of several picoseconds. These results indicate the presence of robust fluctuating charge order that survives well beyond the established CDW phase boundary. Furthermore, these fluctuations are enhanced near a doping-tuned quantum phase transition at $x^{\ast }\approx 0.15$, which coincides with a local minimum in the superconducting $T_{\mathrm{c}}$ double-dome. Additional measurements on Ti- and K-substituted samples confirm that this behavior is intrinsic to hole doping and not tied to disorder. Overall, our findings suggest that CDW fluctuations play a central role in the electronic phase diagram of $A$V${}_3$Sb${}_5$ and may mediate or compete with superconductivity.

References in corpus (23)

• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Unconventional Fermi surface instabilities in the Kagome Hubbard Model
• Charge density waves and electronic properties of superconducting kagome metals
• Superconductivity in the ${\mathbb{Z}}_2$ kagome metal KV${}_3$Sb${}_5$
• Three-dimensional charge density wave and robust zero-bias conductance peak inside the superconducting vortex core of a kagome superconductor CsV${}_3$Sb${}_5$
• Superconductivity and normal-state properties of kagome metal RbV3Sb5 single crystals
• Fermi surface mapping and the nature of charge density wave order in the kagome superconductor CsV${}_3$Sb${}_5$
• Theoretical prediction of a strongly correlated Dirac metal
• Doped Kagome System as Exotic Superconductor
• Fermi level tuning and double-dome superconductivity in the kagome metals CsV${}_3$Sb${}_{5-x}$Sn${}_x$
• Coherent phonon spectroscopy and interlayer modulation of charge density wave order in the kagome metal CsV${}_3$Sb${}_5$
• Charge-density-wave-induced bands renormalization and energy gaps in a kagome superconductor RbV3Sb5
• Manipulation of Jeff=3/2 states by tuning the tetragonal distortion
• Unconventional charge density wave and photoinduced lattice symmetry change in Kagome Metal CsV${}_3$Sb${}_5$ probed by time-resolved spectroscopy
• Geometry of the charge density wave in kagom$\acute{e}$ metal AV${}_3$Sb${}_5$
• Structural evolution of the kagome superconductors $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, and Cs) through charge density wave order
• Optical study of RbV${}_3$Sb${}_5$: Multiple density-wave gaps and phonon anomalies
• Revealing the orbital origins of exotic electronic states with Ti substitution in kagome superconductor CsV3Sb5
• Complete miscibility amongst AV${}_3$Sb${}_5$ kagome superconductors: design of mixed A-site AV${}_3$Sb${}_5$ (A: K, Rb, Cs) alloys
• Revealing Rotational Symmetry Breaking Charge-density Wave Order in Kagome Superconductor (Rb, K)V${}_3$Sb${}_5$ by Ultrafast Pump-probe Experiments
• Coherent Phonon Pairs and Rotational Symmetry Breaking of Charge Density Wave Order in the Kagome Superconductor CsV${}_3$Sb${}_5$
• Interplay of superconductivity and charge-density-wave order in kagome materials
• Evolution of charge correlations in the hole-doped kagome superconductor CsV${}_{3-x}$Ti${}_x$Sb${}_5$

Cited by in corpus (1)

• Evolution from three-dimensional charge density wave to one-dimensional stripe order in CsV${}_{3-x}$Ti${}_x$Sb${}_5$