Lowest-energy endohedral fullerene structure ofSi60 from a genetic algorithm and density-functional theory

Abstract

The lowest-energy structure of theSi60 cluster has been determined from an unbiased search using a genetic algorithm(GA) with the tight-binding model followed by local optimization of ‘hand-made’structures using density-functional theory (DFT). GA simulations show thatSi60 tends to adopt endohedral fullerene configurations. A large number ofisomers with different stuffing/cage ratio and cage configuration werethen constructed and optimized at DFT level. An endohedral fullerene ofSi12@Si48 was found to be most stable; it is energetically preferred to the hollowIh cage by 12.371 eV and to a previously proposed lowest-energy structure by4.841 eV. The competition between different structural growth patterns atSi60 is discussed.