Molecular dynamics simulations of nanocarbons at extreme conditions

摘要

We present a molecular dynamics study of carbon nanoparticles (980 and 10034 atoms) under high temperatures (1000 - 7000 K) and pressures (2 - 45 Gpa) using the reactive LCBOPII potential [Los et al, Phys. Rev. B, 72: 214102, 2005], At low pressures, the most stable phase structures of these clusters correspond to the onion structure, whereas at high pressure the big cluster exhibits the diamond structure as the most stable one. The melting mechanism depends upon the structure, initiated in the core in the case of an onion cluster and at the surface for the nano-diamond. A schematic phase diagram is proposed, that takes into account the finite size effects.