Raman study of lattice dynamics in the Weyl semimetal TaAs

We report a polarized Raman study of the Weyl semimetal TaAs. We observe all the optical phonons, with energies and symmetries consistent with our first-principles calculations. We detect additional excitations assigned to multiple-phonon excitations. These excitations are accompanied by broad peaks separated by 140 cm(-1) that are also most likely associated with multiple-phonon excitations. We also noticed a sizable B-1 component for the spectral background, for which the origin remains unclear.