Quasiparticles with Weyl dispersion can display an abundance of novel topological, thermodynamic and transport phenomena, which is why novel Weyl materials and platforms for Weyl physics are being intensively looked for in electronic, magnetic, photonic and acoustic systems. We demonstrate that conducting materials in magnetic fields generically host Weyl excitations due to the hybridization of phonons with helicons, collective neutral modes of electrons interacting with electromagnetic waves propagating in the material. Such Weyl excitations are, in general, created by the interactions of helicons with longitudinal acoustic phonons. In polar crystals, an additional type of Weyl excitations comes from the interaction between helicons and longitudinal optical phonons. Such excitations can be detected in X-ray and Raman scattering experiments. The existence of the Weyl excitations involving optical phonons in the bulk of the materials also leads to the formation of topologically protected surface arc states that can be detected via surface plasmon resonance.
About the presenter
Dmitry Efimkin is a Scientific Research Associate at Monash University. He is interested in condensation of spatially separated electrons and holes and manifestations including dipolar superfluidity, as part of FLEET’s Research Theme 2, Exciton Superfluids.