Influence of ion-ion correlation on Na plus transport in Na2Ni2TeO6: molecular dynamics study

Molecular dynamics (MD) study of Na+ transport in Na2Ni2TeO6 is performed systematically with varying strength of Na+-Na+ short range repulsions to understand the physical principle governing ion transport mechanism. Na+ diffusion is enhanced by nearly an order of magnitude with reduced Na+-Na+ short range repulsion within the studied range. A similar behavior is also observed in other systems, e.g., AgI and Na2Zn2TeO6, where mobile ions are located closely. The Na+ ion occupancy in Na2Ni2TeO6 shows a significant shift from Na1 to Na2 sites gaining some degree of correlation. The study also emphasizes how mobile ion size influences the ionic diffusion. The fresh insight such as microscopic migration pathways, energy barriers, and jumping mechanism of Na+ are derived from the study.