Molecular dynamics study of disordering, roughening, and premelting of the Pb(110) surface

Abstract

Molecular dynamics simulations incorporating a many-body (glue) potential have been used to investigate the atomic structure and dynamics of the Pb(110) surface in the range from room temperature up to the bulk melting point. The surface region of Pb(110) begins to disorder approximately at 320 K, via the generation of vacancies and the formation of an adlayer. At about 400 K, adatoms begin to form so-called ‘local steps’ (small clusters of 2–3 atoms). The proliferation of atomic steps is observed above 400 K. Above 450 K, adatoms begin to collect in ‘large’ clusters (10–20 atoms), that can be associated with the beginning of the roughening transition. The anisotropic six-vertex model has been used to calculate a roughening transition temperature of T R 6V ≈ 436 K. The onset of a quasiliquid surface region is observed around a wetting temperature of T 0 ≈ 520 K. The calculated values of the roughening transition temperature as well as the wetting temperature are in a good agreement with recent high-resolution low-energy diffraction measurements.