Tunable topology, Hall response, and spin-textures in bicircularly polarized light illuminated altermagnets

Abstract: Altermagnets, featuring non-relativistic spin splitting, have drawn enormous attention due to their intriguing properties. Here, we investigate the effects of shining bicircularly polarized light (BCL) on altermagnets with Rashba spin-orbit coupling. We discover a remarkable tunability of topology, spin-textures, and Fermi surfaces of altermagnets by means of BCL illumination, going beyond monochromatic light. We illustrate a cascade of topological phase transitions controllable by BCL and demonstrate how these transitions are reflected in the anomalous Hall response of the altermagnet. Furthermore, we show that the spin-textures and Fermi surfaces can be directly tuned by the relative phase of the BCL, stemming from the underlying symmetry changes. Our findings can pave the way for effectively controlling altermagnetic materials with structured light.