Unconventional charge order and superconductivity in kagome materials AV₃Sb₅

Lattice geometry, topological electron behavior, and the competition between different possible ground states all have a role in determining the properties of materials with a kagome lattice structure. In particular, the compounds KV₃Sb₅, CsV₃Sb₅ and RbV₃Sb₅ all feature a kagome net of vanadium atoms. These materials have recently been shown to exhibit superconductivity at low temperature and charge order at high temperature, revealing a connection to the underlying topological nature of the band structure. I will summarize the experimental evidence, in particular regarding the nature of the charge order, and provide a theoretical interpretation of it. Particularly exciting is the potential realization of time-reversal symmetry breaking charge order with finite relative angular momentum in this material class. Both of these are long-sought properties in charge ordered ground states, which have important repercussions on the topology of the resulting ground state.