Spontaneous alloying in binary metal microclusters:  A molecular dynamics study

Microcanonical molecular-dynamics study of spontaneous alloying (SA), which is a manifestation of fast atomic diffusion in a nanosized metal cluster, is done in terms of a simple two-dimensional binary Morse model. Important features observed by Yasuda and Mori are well reproduced in our simulation. The temperature dependence and size dependence of SA phenomena are extensively explored by examining long-time dynamics. The dominant role of negative heat of solution in completing SA is also discussed. We point out that a presence of melting surface induces the diffusion of core atoms even if they are solidlike. In other words, the surface melting at substantially low temperature plays a key role in attaining SA.