The Edge Effects on the Melting Process of Two-dimensional Gallium Nitride

Abstract The melting process of two-dimensional Gallium Nitride was studied using a comprehensive Molecular Dynamics simulation. The Stilinger-Weber potential was applied to the interactions between Ga and N. Four configurations with the same number of atoms (10000) but different armchair/zigzag edge ratios were studied to investigate the influence of the length of the zigzag and armchair edges on the melting process. Then, the number of atoms in the above four configurations was increased to 19600 atoms to investigate the effect of the number of atoms on the melting process. The results show that in the range of this study: the length of the zigzag and armchair edges does not affect the phase transition (first-order case); in both cases, the number of atoms (10000 and 19600 atoms), the melting point of four configurations is approximately 3790 K, indicating that the stable range of the number of atoms in the configuration is from 10000 to 19600 atoms. The atomic mechanism of the melting process is studied: the phase transition exhibits a first type; the atomic mechanism of the melting process is analyzed based on certain criteria such as the radial distribution function, angular distribution function, coordination number, and Lindemann criterion for the two-dimensional case; the critical value of the Lindemann criterion for the two-dimensional case of γ_3 is approximately 0.092; the solid-like and liquid-like atoms are classified based on the critical value of the Lindemann criterion during the heating process.