Multifold Weyl nodes in a nonsymmorphic garnet compound*

In condensed matters, now, many systems show linear band crossings of 4-fold Dirac nodes or 2-fold Weyl nodes, which have been sought for a long time in high energy physics. Recently, multi-fold nodes, which have no high energy counterpart, have been also proposed, e.g., 3-, 6-, and even 8-fold Weyl nodes. However, except triple-node points, no experimental realization has been successful yet. In this presentation, we will introduce an interesting real system with various exotic Weyl nodes, lying not far away from the Fermi energy.
Using first principles calculations, we will address a nonsymmorphic ferrimagnetic garnet insulator with the Ia-3d space group (No.230). In the absence of spin-orbit coupling (SOC), this system shows various magnetic multifold Weyl nodes, in particular, of 4- and 6-folds. These nodes with nonzero Chern numbers are due to a combination of several crystalline symmetries including inversion and glide reflection symmetries. Furthermore, we will discuss on the topological nature of the unconventional Weyl nodes by an effective Hamiltonian analysis.