Phonons in Copper Diphosphide (CuP₂): Raman Spectroscopy and Lattice Dynamics Calculations

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Copper diphosphide (CuP2) is an emerging semiconductor with potential in energy applications.
• Previous research has focused on CuP2 functionality, neglecting its vibrational properties.

Purpose of the Study:

• To provide a reference Raman spectrum for copper diphosphide (CuP2).
• To perform a complete experimental and theoretical analysis of CuP2's vibrational properties.
• To assign all Raman active modes and understand lattice dynamics.

Main Methods:

• Raman spectroscopy on polycrystalline CuP2 thin films.
• Detailed spectral deconvolution using Lorentzian curves.
• Density Functional Theory (DFT) calculations for phonon dispersions, phonon density of states (PDOS), and infrared (IR) active modes.

Main Results:

• Identification and symmetry assignment of all 9A_g and 9B_g Raman active modes.
• Microscopic understanding of experimental phonon lines through PDOS and phonon dispersion calculations.
• Theoretical prediction of IR active modes and simulation of the IR spectrum.

Conclusions:

• Good agreement between experimental and DFT-calculated Raman spectra of CuP2.
• Establishes a reference platform for future research on CuP2 vibrational properties.
• Provides insights into the lattice dynamics of this promising semiconductor material.