Extreme Electron-Phonon Coupling in Topological Semimetal NbGe₂.

Weyl semimetals are topological systems that have generated considerable interest due to their transport properties. One of the mechanisms that may play an important role in the manifestation of these transport properties is electron-phonon coupling. Previous optical experiments done on various Weyl semimetals have already shown phonon linewidths deviating from the usual model of anharmonic decay. Here we report on Raman measurements performed on a new topological semimetal. Careful analysis reveals the lifetime is consistent with electron-phonon coupling far in excess of the anharmonic decay channels.