Discovery of coexisting Dirac and triply degenerate magnons in a three-dimensional antiferromagnet.

ABSTRACT: Topological magnons are emergent quantum spin excitations featured by magnon bands crossing linearly at the points dubbed nodes, analogous to fermions in topological electronic systems. Experimental realisation of topological magnons in three dimensions has not been reported so far. Here, by measuring spin excitations (magnons) of a three-dimensional antiferromagnet Cu₃TeO₆ with inelastic neutron scattering, we provide direct spectroscopic evidence for the coexistence of symmetry-protected Dirac and triply degenerate nodes, the latter involving three-component magnons beyond the Dirac-Weyl framework. Our theoretical calculations show that the observed topological magnon band structure can be well described by the linear-spin-wave theory based on a Hamiltonian dominate

SUBMITTER: Bao S 

PROVIDER: S-EPMC6030121 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature