Circularly polarized light irradiated ferromagnetic ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$: A possible ideal Weyl semimetal

The interaction between light and nontrivial energy band topology allows for the precise manipulation of topological quantum states, which has attracted intensive interest in condensed-matter physics. In this work, using first-principles calculations, we studied the topological transition of ferromagnetic (FM) ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ upon irradiation with circularly polarized light (CPL). We revealed that the ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ can be driven from an FM insulator to a Weyl semimetal with a minimum number of Weyl points, i.e., two Weyl points (WPs) in systems without time-reversal symmetry. More importantly, in FM ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ with an out-of-plane easy magnetization axis, we found that the band dispersion of the WP evolves from type-II to type-III and finally to type-I when the light intensity increases. Moreover, we show that the profile of the characteristic Fermi arc of the Weyl semimetal phase is sensitive to changes in light intensity, which enables efficient manipulation of the Fermi arc length of FM ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ in experiments. In addition, for FM ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ with an in-plane easy magnetization axis, the system becomes a type-I Weyl semimetal under CPL irradiation. With controllable band dispersion, the length of the Fermi arc, and a minimum number of WPs, our results indicate that CPL-irradiated FM ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ is an ideal platform for the study of novel transport phenomena in Weyl semimetals with distinct band dispersion.