Condensation of preformed charge density waves in kagome metals

Abstract

Charge density wave (CDW) is a spontaneous spatial modulation of electric charges in solids whose general microscopic descriptions are yet to be completed. Layered kagome metals of $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs) provide a unique chance to realize its emergence intertwined with dimensional effects as well as their special lattice. Here, based on a state-of-the-art molecular dynamics simulation, we uncover that the phase transition to charge ordered states in kagome metals is a condensation process of incoherently preformed CDWs. We demonstrate that charge modulation first preforms on each kagome layer at a well defined temperature but its phase fluctuation proliferates across the entire layers with a $10^5$ times slower frequency than typical phonon vibrations until reaching its freezing temperature. We find that the fluctuation is not random but confined to a limited number of states as a consequence of unavoidable degeneracy in stacking layered charge orders. As the size of interfacial alkali atom increases, the fluctuating phases are shown to counterbalance the condensation of orderings, resulting in a maximized transition temperature for RbV${}_3$Sb${}_5$. Our results resolve several controversial observations on their CDW formations and highlight a crucial role of interlayer interactions for the charge ordering in kagome metals.

References in corpus (13)

• 2D materials and van der Waals heterostructures
• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Gate-tunable Phase Transitions in 1T-TaS${}_2$
• Topological kagome magnets and superconductors
• Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS3
• Superconductivity and normal-state properties of kagome metal RbV3Sb5 single crystals
• Unusual competition of superconductivity and charge-density-wave state in a compressed topological kagome metal
• Three-state nematicity and magneto-optical Kerr effect in the charge density waves in kagome superconductors
• Charge order breaks time-reversal symmetry in CsV${}_3$Sb${}_5$
• 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
• Crucial role of out-of-plane Sb-$p$ orbitals in Van Hove singularity formation and electronic correlation for superconducting Kagome metal CsV${}_3$Sb${}_5$
• Charge density wave order and fluctuations above T${}_{CDW}$ and below superconducting T${}_c$ in the kagome metal CsV${}_3$Sb${}_5$

Cited by in corpus (5)

• Fluctuated lattice-driven charge density wave far above the condensation temperature in kagome superconductor KV${}_3$Sb${}_5$
• Distinct pressure evolution of superconductivity and charge-density-wave in kagome superconductor CsV${}_3$Sb${}_5$ thin flakes
• Unveiling the nature of electronic transitions in RbV${}_3$Sb${}_5$ with Avoided Level Crossing $\mu$SR
• Symmetry-broken ground state and phonon mediated superconductivity in Kagome CsV${}_3$Sb${}_5$
• Super Moiré Domain Tessellations, Sliding Ferroelectricity, and Reconfigurable Quantum Dot Arrays in Twisted Trilayer Hexagonal Boron Nitride