Creating Weyl nodes and controlling their energy by magnetization rotation

The authors propose that in magnetic Weyl semimetals the orientation of the magnetization can serve as a clean and in-situ approach to tune the energy of the Weyl nodes to the Fermi surface. Density-functional calculations in Co${}_{3}$Sn${}_{2}$S${}_{2}$ show that rotation of the magnetization away from the easy-axis leads to creation and annihilation of Weyl nodes and to changes in the energy of the Weyl nodes of the order of 100 meV. The same phenomenology is found in the elementary magnet hcpCo, suggesting that the results may be of interest for a broad class of magnetic materials.