MnPdGe: A Quasi-1D Kagome Weyl Nodal Ring Semimetal for Next-Generation Spin-Orbit Torque and Magneto-Optical Applications

The interplay between magnetism and topology has opened up promising avenues for spintronics and quantum technologies. Topological materials, with distinctive band structures and enhanced Berry curvature, enable dissipationless transport and pronounced linear response properties. Here, we report a first-principles study of MnPdGe, which crystallizes in a distorted quasi-1D kagome structure. Our calculations reveal nodal-line features, multiple Weyl nodal rings, and triple-point fermions in the electronic spectra, with their nontrivial topological nature confirmed by Berry phase calculations. Spin-orbit coupling (SOC) induces finite Berry curvature, leading to sizable intrinsic anomalous Hall and anomalous Nernst conductivities. Magneto-optical calculations further predict a polar Kerr rotation of about 1.2^°under normal incidence, demonstrating its potential for next-generation magneto-optical (MO) recording devices. Furthermore, the significant spin Hall conductivity can generate self-induced spin-orbit torque (SOT), making MnPdGe a promising candidate for future topological spintronic applications.