Optical and transport anisotropies in spin-textured altermagnets

Abstract: Spin textures are ubiquitous in antiferromagnets, yet their consequences for altermagnets remain largely unexplored. We show that spatial variations of the Néel order act on the low-energy electrons as effective gauge fields, leading to strong anisotropies in both dc transport and optical absorption, even without intrinsic spin-orbit coupling. As a concrete example, we analyze a coplanar spin helix and predict that the principal axes of the conductivity and linear dichroism are set by the helix wave vector and can be tuned by the texture geometry. Our results point to polarization-resolved optics and anisotropic transport as direct probes of textured altermagnetic states, and suggest a simple route to direction-selectivity.