  The semimetal NbIrTe4 has been proposed to be a Type-II Weyl semimetal with 8
pairs of opposite Chirality Weyl nodes which are very close to the Fermi
energy. This topological electronic structure is made possible because of the
broken inversion symmetry of NbIrTe4 which is an orthorhombic crystal with Td
symmetry. Using micro-Raman scattering as a probe, we observe the frequencies
and symmetries of 19 phonon modes (ranging from 40 to 260 cm-1) in this
material and compare to Density Functional Theory calculations. Using angular
and polarization resolved Raman scattering for green (514 nm) and red (633 nm)
laser excitation, we show that it is possible to extract the excitation energy
dependence of the Raman tensor elements associated with each measurable phonon
mode. We show that these tensor elements vary substantially in a small energy
range which reflects a strong variation of the electron-phonon coupling for
these modes.
