Nonlinear electron-phonon coupling drives light-induced symmetry switching in charge-density waves
This paper presents a first-principles theory based on Heisenberg structural dynamics that identifies nonlinear electron-phonon coupling as the primary mechanism driving light-induced symmetry switching and ultrafast melting of charge-density wave order in monolayer TiSe, while accounting for quartic lattice anharmonicities and photoexcitation-induced potential energy surface modifications.