Effect of intense laser irradiation on the lattice stability of Cu and Ag

The structural, electronic and lattice-dynamical properties of Cu and Ag at different electronic temperatures have been investigated via density functional calculations. The results of electronic density of state indicate that both of Cu and Ag are still metals after intense laser irradiation. The smaller width of the DOS for Cu and Ag induce a motion towards higher energies when electronic temperature is elevated. The calculated phonon frequencies of Cu and Ag at high-symmetry points of the Brillouin zone (BZ) at Te = 0 eV show a good agreement with the experimental values and other calculations. When Cu and Ag undergo a sharp increase of its electronic temperature, the phonon frequencies of Cu and Ag experiment a significant hardening. The predicted melting temperatures of Cu and Ag undergo a sharp increase after intense laser irradiation. We interpret this as the clear signature of the stabilizing effect of intense laser irradiation on the Cu and Ag lattices, which in turn may result in a significant time delay for the lattice to melt.