AV₃Sb₅ (A=K, Rb, Cs)—A New Class of Topological Kagome Metals Hosting Intertwined Charge Density Wave Order and Superconductivity

Kagome metals are fascinating materials capable of hosting electronic states hosting an interplay between topologically nontrivial electronic states and correlated electron phenomena. This interplay is born from the Dirac points, flatbands, and saddle-points endemic to the kagome lattice at select filling fractions. The discovery of a new class of kagome metals of the form AV₃Sb₅ with A=K, Cs, or Rb has recently provided a unique setting for exploring the interplay between Z₂ electronic topology and intertwined charge density wave and superconducting orders. These compounds host a kagome lattice of nonmagnetic vanadium ions with an electron-filling that places the Fermi level near the saddle-points and their corresponding van Hove singularities. Nesting effects due to this divergent density of states are predicted to stabilize a variety of unusual states, ranging from charge density wave order that breaks time reversal symmetry to unconventional superconductivity. Here I will present some of our recent work exploring the phase transitions and broken symmetries in these materials.