Monte Carlo simulation of order-disorder transformation in nano particles of Cu 3 Au alloy

摘要: The ground state energy of nano particles of the Cu3Au alloy is calculated by utilizing the modified embedded atom method(MEAM), and a computer simulation is made of the order-disorder transition therein by Monte Carlo method with the many-body potential obtained by MEAM. The calculations have been made for three kinds of model crystals of nano particles with 2 nm and 3 nm in diameter, containing 321 and 1061 atoms, respectively, and of a bulk with a size of 5 × 5 × 5 unit cells, on which the periodic boundary condition is imposed. As a result, it is found that the difference in ground state energy between perfectly ordered and disordered states becomes less in nano particles than in the bulk, and that the critical temperature T decreases markedly with decreasing particle size. According to our previous experiments, there seems to be a certain critical size for the atomic ordering in the nano particles …