Semiclassical description of electron dynamics in extended systems under intense laser fields

[摘要] We propose a semiclassical approach based on the Vlasov equation to describe the time-dependent electronic dynamics in a bulk simple metal under an ultrashort intense laser pulse. We include in the effective potential not only the ionic Coulomb potential and mean-field electronic Coulomb potential from the one-body electron distribution but also the exchange-correlation potential within the local-density approximation (LDA). The initial ground state is obtained by the Thomas-Fermi model. To numerically solve the Vlasov equation, we extend the pseudoparticle method, previously used for nuclei and atomic clusters, to solids, taking the periodic boundary condition into account. We apply the present implementation to a bulk aluminum (fcc) conventional unit cell irradiated with a short laser pulse. The optical conductivity, refractive index, extinction coefficient, and reflectivity as well as energy absorption calculated with the Vlasov-LDA method are in excellent agreement with the results by the time-dependent density-functional theory and experimental references.

[关键词] LOCAL-DENSITY APPROXIMATION;METAL-CLUSTERS;ABLATION;FEMTOSECOND;PSEUDOPOTENTIALS;MECHANISMS;HARMONICS;ALGORITHM;MODELS