A combined first principles and phenomenological approach for the modeling of coherent phonons in materials*

Coherent phonons in materials can elucidate the interactions between electronic, optical, and lattice degrees of freedom, and have potential applications in nonlinear phononics and coherent lattice control. We study coherent phonons in bismuth and antimony using first principles density functional theory and a phenomenological classical equation of motion. By explicitly calculating and interpolating both the potential energy surface and the frequency-dependent macroscopic dielectric function across all three optical phonon modes in these materials, we are able to map out the landscape of interactions between the lattice and the optical response of the material. We apply this approach to reproduce classic results in the field and compare expressions for the coupling of lattice dynamics with electronic response. We comment on the range of applicability of our methodology and the potential for first-principles-informed surrogate models for material response.