Landau theory of charge density waves in AV₃Sb₅.

In recent years, the AV₃Sb₅ (A=K, Cs, Rb) family of Kagome metals has attracted a lot of attention for its potential as a platform to study a plethora of interesting physics such as strong correlation, topology, van Hove singularities, superconductivity (SC), magnetism, and charge density waves (CDW). Motivated by experiments on the AV₃Sb₅ Kagome metals that indicate a CDW formation and a SC formation in the CDW state, we used a continuum model to study how interactions can induce density waves on a Kagome lattice. We found that the system can form a 3Q charge density wave but could also spontaneously break time-reversal symmetry by forming orbital currents. In addition, three-dimensional effects coming from interlayer coupling were identified as a possible mechanism to generate a three-dimensional density wave structure as well as C₆ symmetry breaking. Lastly, the domain walls between different CDW states were considered and the possibility of time-reversal symmetry breaking caused by the formation of domain walls was studied.