A new cubic Ia3̅d crystal structure observed in a model single component system by molecular dynamics simulation

Abstract

Abstract In our molecular dynamics simulations of the system of identical particles interacting through the harmonic-repulsive pair potential, we observed the formation of a cubic crystal structure that belongs to the Ia3̅d (#230) crystallographic space group. This crystal structure has not been previously seen either in experiments or in computer simulations, though its framework topology has been known from theoretical crystallographic considerations. Its unit cell contains 16 atoms, occupying only (16b) Wyckoff site, and arranged as two mutually intertwined unconnected networks with packing fraction of 0.37. The appearance of this structure is explained by the soft repulsive nature of the interaction potential. The observed Ia3̅d structure extends the small number of cubic structures formed in single component systems with spherically symmetric pair potentials in MD simulations. We speculate that materials with such structure could be found in soft matter systems or in selected crystals under high pressure.