Emergence of Quasi-One-Dimensional van Hove Singularity in Kagome Metal RbV₃Sb₅

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Divergence in the density of states (DOS) near the Fermi energy is crucial for electron correlations.
• Van Hove singularities (vHS) often cause this DOS divergence, with characteristics dependent on electron dispersion dimensionality.
• Surface atomic arrangements can modify electron dispersion dimensionality and thus vHS.

Purpose of the Study:

• Investigate how surface atomic arrangements in V-based Kagome metals (AV3Sb5) affect electron correlations.
• Explore the impact of specific atomic configurations on DOS divergence and charge density waves.

Main Methods:

• Theoretical analysis of electronic structure in AV3Sb5 materials.
• Focus on the role of Rb atom arrangement in modifying the Kagome lattice potential.

Main Results:

• Saddle-shaped dispersion in AV3Sb5 leads to two-dimensional vHS.
• Linear arrangement of Rb atoms creates a one-dimensional localized potential.
• Observed significantly increased DOS divergence and augmented charge density wave.

Conclusions:

• Surface atomic arrangement can reduce effective dimensionality, enhancing electron correlations.
• The 1D potential from Rb atoms reinforces electronic correlations in AV3Sb5.
• This reinforcement drives the observed increase in DOS divergence and charge density waves.