Impurity effects on photo-induced multiply quantized electronic vortices

Previous work on massive two-dimensional Dirac materials has shown that exposing such materials to vortex light beams allows for photo-induced multiply quantized vortices and a conserved angular momentum operator [1]. However, this work relies on very specific conditions: circularly polarized light and a pristine sample. Our work investigates how resistant these vortex states are to realistic lab conditions: light with slightly elliptic polarization and dilute impurities. The vortices appear quite robust to impurities of varying strengths, widths, and placements [2]. Both the conserved angular momentum operator and robustness are verified numerically by symmetries presented in both the quasienergy spectra and radial wavefunctions.