Theoretical and Computational Analysis of Electron Phonon Coupling in CsV₃Sb₅

CsV₃Sb₅ exhibits both charge density wave and superconducting phases. It is part of a class of kagome lattices that also have a notable band structure consisting of a Dirac dispersion and Weyl nodes. Because of apparent competition between the charge density wave (CDW) and superconductivity, it is critical to understand the interplay between electronic and phonon responses. In this talk we will present theoretical and computational investigation of the Raman spectra and electron-phonon coupling in this material, both in the CDW and in the undistorted arrangement, examining the electronic coupling to A1g and E2g phonons. A Fano lineshape for the A1g phonon indicates a strong coupling to the electron continuum. We observe that the line shape changes in the CDW state and a general agreement between first principle investigation and experiment is found.