Comparative study of anharmonicity : Ni „ 111 ... , Cu „ 111 ... , and Ag „ 111 ...

We present a comparative study of the structure and the dynamics of the most close packed surface of Ni, Cu, and Ag from near room temperature up to 0.9Tm , using molecular dynamics simulations and interaction potentials from the embedded atom method. Calculated shifts in the surface phonon frequencies, the broadening of their linewidths, and the variations in the mean square vibrational amplitudes of surface atoms, as a function of temperature, indicate that anharmonic effects are small on these surfaces. The surface thermal expansion of these three ~111! surfaces is also found to be smaller than that of the respective ~100! and ~110! surfaces. Additionally, we do not find any premelting or pronounced disordering on these surfaces, in the temperature range considered.