Signature of chiral anomaly in TaP through phonon dynamics

Recent theoretical predictions discussed the possibility of detecting chiral anomaly based on phonon spectra as the exotic electronic degrees of freedom in a Weyl semimetal play an important role to influence the phonon structure. I will discuss measurements made of phonon excitations on a high-quality single crystal sample of type-I Weyl semimetal TaP using inelastic neutron and x-ray scattering spectroscopies. These measurements indicate the presence of phonon softening near the Weyl nodes which is driven by the coupling between the chiral Weyl fermions and phonons. We also observe that this coupling differs between the W1 and W2 Weyl nodes. These results provide a method to extract valuable information about the sought-after electron-phonon coupling strength.