Anharmonic Strong-Coupling Effects at the Origin of the Charge Density Wave in CsV 3 Sb 5
The formation of Charge Density Waves (CDW) in CsV3Sb5 is driven by strong anharmonic electron-phonon and phonon-phonon coupling, not weak coupling. This strong interaction results in a large electronic energy gap and an asymmetric amplitude mode (AM) with a unique Fano resonance shape, suggesting the CDW transition is governed by cooperative lattice dynamics.