Photo-induced Multiply Quantized Vortex States in Dirac-like Materials

Light polarization and intensity are regularly used to tune the interaction with matter to induce band hybridizations and topological phase transitions. Further control is achieved by manipulating the spatial dependence of the field’s phase, as demonstrated by vortex light beams carrying orbital angular momentum [1]. This work explores the consequences of light-matter interaction for a two-dimensional massive Dirac-like system subjected to a monochromatic vortex light beam. Utilizing Floquet’s formalism, we introduce the exact definition of the total angular momentum in Floquet space and identify the polarizations for its conservation. Using the one-photon approximation, we map the resulting Hamiltonian to the model of an s-wave superfluid hosting multiple quantized vortex core states [2]. The procedure allows us to analytically determine the number of vortex states that appear in our system at low energies. We extend these results by applying the Bessel decomposition method to numerically diagonalize the full Floquet Hamiltonian in the resonant regime. We present a complete description of the photon-dressed electronic vortex states that emerge from the irradiated system in terms of the angular momentum-dependent dispersion relation, vorticity, and real-space extension.

[1] Y. Shen, et al., Light: Science & Applications 8, 1–29 (2019)

[2] A. Prem, S. Moroz, V. Gurarie, and L. Radzihovsky, PRL 119, 067003 (2017)