Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 86: Electronic Structure of Surfaces: Spectroscopy, Surface States II
O 86.9: Talk
Thursday, March 20, 2025, 17:00–17:15, H2
Higher-order van Hove singularities in Kagome metal RbV3Sb5 — •Gahee Lee — Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea
The divergence of the density of states (DOS) near the Fermi energy is crucial for enhancing electron correlations. Van Hove singularities (vHS) commonly cause this DOS divergence, with their properties determined by the dimensionality of electron dispersion. The atomic arrangement on the surface of layered materials can influence the effective dimensionality of electron dispersion, thereby shaping the characteristics of vHS. In V-based Kagome metals RbV3Sb5 (A = K, Rb, and Cs), the saddle-shaped dispersion results in two-dimensional vHS. Interestingly, the surface arrangement of atoms in a Kagome lattice can modify the effective dimensionality of electron dispersion, affecting the strength of electron correlations. In this study, we present a novel approach to enhancing electron correlation by arranging the surface Rb atoms. The resulting higher-order vHS significantly enhances the divergence of DOS and strengthens charge density waves in V-based Kagome metals.
Keywords: Charge density wave; Higher-order van Hove singularity; V-based Kagome metal