Two-step melting of the Weeks–Chandler–Anderson system in two dimensions

We present a detailed numerical simulation study of two dimensional system particles interacting via the Weeks-Chandler-Anderson potential, repulsive part Lennard-Jones potential. With reduction density, shows two-step melting: continuous melting from solid to hexatic phase, followed by first order liquid. The solid-hexatic is consistent with Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) scenario and dislocation unbinding. fluid on other hand, dominated formation string defects at hexatic-fluid interfaces.