Copper diphosphide (CuP2) is an emerging binary
semiconductor
with promising properties for energy conversion and storage applications.
While functionality and possible applications of CuP2have
been studied, there is a curious gap in the investigation of its vibrational
properties. In this work, we provide a reference Raman spectrum of
CuP2, with a complete analysis of all Raman active modes
from both experimental and theoretical perspectives. Raman measurements
have been performed on polycrystalline CuP2thin films
with close to stoichiometric composition. Detailed deconvolution of
the Raman spectrum with Lorentzian curves has allowed identification
of all theoretically predicted Raman active modes (9Agand
9Bg), including their positions and symmetry assignment.
Furthermore, calculations of the phonon density of states (PDOS),
as well as the phonon dispersions, provide a microscopic understanding
of the experimentally observed phonon lines, in addition to the assignment
to the specific lattice eigenmodes. We further provide the theoretically
predicted positions of the infrared (IR) active modes, along with
the simulated IR spectrum from density functional theory (DFT). Overall
good agreement is found between the experimental and DFT-calculated
Raman spectra of CuP2, providing a reference platform for
future investigations on this material.