Exotic Topological properties in compensated half-metallic inverse-Heusler systems*

Recently three-dimensional (3D) topological features mixing with zero-dimensional (0D) band-crossings (Dirac, Weyl, multi-Weyl, and triple-nodal points [TNPs]) have stimulated further interest. An exotic phase, so called nexus fermion, has been expected when a 0D TNP coincides with a 1D nodal line. The nexus fermions are a yet more intricate excitation that have been proposed, but no realistic system has been proposed for such an exotic phase.
In this presentation, we will address a unique topological metallic system displaying simultaneous pure spin WPs, TNPs, nodal loops, and nexus fermions in the absence of (minor) spin-orbit coupling (SOC), in Cr-based inverse-Heusler compensated half-metals with neither inversion nor time-reversal symmetry, using density functional theory-based calculations. This combination gives rise to fully spin polarized nexus fermions, in a system with broken time-reversal symmetry but negligible macroscopic magnetic field. The observed high Curie temperature of 750 K and calculated SOC hybridization mixing of several meV should make these nexus fermions readily measurable.