Photoinduced band renormalization effects in square-net materials

Out-of-equilibrium effects provide an elegant pathway for probing and understanding the underlying physics of correlated materials. In particular, controlling electronic band structure properties using ultrafast optical pulses has shown promise for creating exotic states of matter by inducing charge density waves, or modifying the fermi velocities of Dirac particles. Of recent interest is band renormalization effects in square-net materials as they possess interesting spectral properties, e.g., nodal lines or axial-Higgs physics. Here we present a theoretical study of out-of-equilibrium effects in the family of nodal line semimetals featuring a square net of atoms. Specifically, we show that the renormalization of the kinetic energy of electrons due to the ultrafast pump field leads to the enhancement of the effective mass and to the shift of the resonant frequencies of the material. Finally, we discuss signatures of such modifications in transient Rayleigh and Raman scattering. Our study demonstrates the potential of this approach in creating photoinduced phases in topological quantum matter through an all-optical route.