A perspective on the electronic instabilities in kagome AV3Sb5

Abstract

The electronic properties of solids are strongly shaped by lattice geometry. A prime example is the kagome lattice, whose band structure features van Hove singularities (vHS), flat bands, and Dirac crossings. These characteristics naturally promote strong electronic correlations. In the kagome metals AV3Sb5, the Fermi level lies close to kagome-derived vHS, placing the system in a regime of heightened electronic susceptibility and correlation-driven instabilities. In this Perspective, we discuss the electronic instabilities observed experimentally in AV3Sb5, outline the physical pictures that we find most compelling, and share our views on the current excitement, open debates, and future opportunities in these materials. We view AV3Sb5 as a uniquely clean platform for exploring how multiple correlated phases coexist, compete, and intertwine on a single Fermi surface, offering a level of conceptual richness comparable to that of the cuprates. Although a lot of information about AV3Sb5 has been collected in recent years, we still lack a clear understanding of each of its electronic phases or their interplay. This Perspective aims to expose the status of the field and cajole a communal effort toward a unified physical description of these compounds.