Weyl magnon in magnetic diamond lattice

Three-dimensional topological nodal semimetals have been intensely studied. Recently, it is proposed that the bosonic analogues of the systems, Weyl magnon semimetals, can be realized in magnetic systems. In the Weyl magnon semimetals, a dispersion relation is described by the relativistic Weyl equation around band touching points, and there are flat surface bands connecting the bulk Weyl points, analogues to the fermi-arc states in Weyl semimetals. Because of the relativistic nature in the dispersion, magnon transport phenomena related to the chiral anomaly are expected. However there are only few systems proposed to possesses the Weyl magnon states. In this talk, we propose a new candidate for Weyl magnon semimetals. We study the magnetic excitations in the ferromagnetic diamond lattice. As a result, we find that the Weyl magnon semimetal can be realized. We also discuss magnon transport induced by electric fields. Since magnons have been gathering attention as low-dissipation carriers in spintronics, electric manipulation of Weyl magnon might provide a new way to realize low-energy-consumption devices.