Transient Dynamics and Fermi Velocity Modulation in Light-Driven Kagome Lattices

In this study, we investigate the transient dynamics of interacting Dirac fermions arranged in a two-dimensional kagome lattice. The structure is subjected to high-frequency, off-resonance, circularly polarized light. By applying the Floquet-Magnus expansion, we derive a low-energy effective Hamiltonian that captures the stroboscopic effects of the applied electromagnetic field. This effective Hamiltonian accurately reproduces the energy dispersion of the original kagome lattice, including the linear Dirac-like dispersion and a distinctive flat band. The external field modifies the Fermi velocity near the Dirac points, influencing carrier transport in applied electric and magnetic fields. This could potentially affect phenomena such as the Hall effect and other transport properties. Furthermore, our analysis suggests the possibility of gap formation at the Dirac point, which could lead to nontrivial band topology and the emergence of Floquet states. While this gap opening has not yet been fully observed in simulations, we explore the dynamics involved and the role of electron-electron interactions in shaping these outcomes.