  Recent advances in ultrashort laser pulse techniques have opened up a wide
variety of applications in both fundamental physics and industrial fields. In
this work, $ab$ $initio$ molecular dynamics simulations based on time-dependent
density functional theory revealed a steady deceleration of lattice distortion
propagation in an aluminum slab with increasing laser pulse intensity. Analysis
of the interatomic force revealed a significant reduction in the harmonic terms
and non-monotonic growth of anharmonicity. This behavior was characterized by
spatially non-uniform force screening by plasmons, which is missing from
Born--Oppenheimer molecular dynamics, and is consistent with the current
interpretation of laser-induced periodic structure patterning. This work
provides a semi-quantitative criterion for modifying the phonon properties of
non-equilibrium systems.
