Tight-binding molecular-dynamics study of melting behaviour of small silicon clu sters

Abstract

The Tight_binding molecular_dynamics(TBMD) has been used to study the melting behaviour of small silicon clusters Sin（n=5—10）. We report the calcu lated res ults of the latent heat of fusion　Δμls and the melting temperature Tm as a function of cluster size. Δμls and Tm　exhibit a s trong dependen ce on cluster size. The melting mechanisms of silicon clusters are distinguished from metal clusters. The melting of metal clusters can be described as a tran sition from a low_energy solid_like structure at low temperatures to a higher_en ergy liquid_like structure at high temperatures. At the transition temperature, metal clusters undergo a dynamics coexistence of the two states, while the silic on clusters undergo an intermediate state which is neither liquid_like structure nor solid_like structure. The melting points obtained by using different calcul ation methods and definitions also have been compared in this work.