Chiral magnons in an altermagnetic Janus Mn₂SeTe Monolayer

Chiral magnons in altermagnets have attracted significant attention due to their unique spin transport phenomenon in the absence of strong spin–orbit coupling. Here, we explore a novel structure, square lattice Janus Mn₂SeTe (s-Mn₂SeTe) monolayer, derived from the antiferromagnetic square lattice MnSe monolayer. Based on first-principles calculations, we investigate the electronic and magnetic properties of s-Mn₂SeTe, revealing its altermagnetic nature and the presence of non-degenerate chiral magnons. We further demonstrate that the manipulation of exchange parameters through lattice strain and carrier doping in altermagnetic s-Mn₂SeTe has a substantial impact on the chiral magnons. This strategy modulates both the spin Seebeck effect and spin transverse transport, potentially even reversing their transport direction. Our findings enhance understanding of altermagnetic properties, suggesting new applications in spintronics.