Diffusion of alkali metal atoms (Li, Na, K) on aluminum nitride and boron nitride nanocages; a density functional theory study

Density functional calculations have been performed to study the diffusion behavior of various alkali metal atoms on the surface of (AlN)12 and (BN)12 nanocages. Alkali metal doped nanocages possess remarkable nonlinear optical response. A number of studies in the literature discuss the structural, electronic, nonlinear and sensor applications of pure and doped X12Y12 nanocages. Alkali metal atom doping at different adsorption sites is reported; however, the information regarding the interconversion barriers for the diffusion of alkali metals on these structures is still unknown. In this study, the barriers for the diffusion of alkali metal atoms (Li, Na, K) on these nanocages are studied at ωB97XD method. The barriers are obtained by scanning potential energy surface along the movement of alkali metals through the nanocage. The barriers for the diffusion of lithium atom on AlN nanocage are found to be higher than BN nanocage. The highest interconversion barrier calculated is 48.77 kcal mol−1 for b66 to r6 movement of lithium atom on AlN nanocage. The lowest migration barrier is observed for sodium movement from r6 to b66 in AlN nanocage.