SFB Extra Seminar

AV₃Sb₅ compounds are layered vanadium antimonides with A = K, Rb, Cs. They form a novel group of kagome metals that exhibit a remarkable range of emergent electronic phases, including superconductivity, charge-density-waves, nematicity, current-loop order, and pair-density-waves. Understanding the nexus between the unique electronic structure of the kagome lattice and this multitude of collective electronic orders is an active area of research and critical for a complete understanding of symmetry breaking in kagome metals. In this talk, I will discuss our recent ARPES studies of van Hove singularities (vHs) from kagome-derived bands in AV₃Sb₅ compounds and their connection to the formation of the period-2 charge-density-wave. The vHs are characterized by two sublattice flavors (p-type and m-type), with the m-type vHs (from V 3dxz and 3dyz orbitals) and the p-type vHs (from V 3dxy and 3dx2–y2 orbitals) all located near the Fermi level. The former band exhibits prominent Fermi surface nesting, while the latter displays the largest gap, suggesting a strong-coupling origin of charge order that likely results from electron-lattice coupling. Additionally, I will present more recent work focusing on the ARPES signatures of band folding in AV₃Sb₅ and their link to the microscopic texture of charge-density-waves and to the emergence of period-4 stripe order and pair-density-wave ordering.