On the diffusion mechanism of some superalkali metal clusters adsorbed on single-layered boron nitride flakes

Functionalisation of single-layer boron nitride flakes (h-BN) with the help of some metal clusters has been a widely explored path for possible applications such as enhancing the optoelectronic response and gas sequestration properties of h-BN. While the thermodynamic properties of metal cluster@h-BN systems are well-known, our present study elucidates the interesting dynamical properties of some superalkali cluster functionalized h-BNs. We study the dynamics of OLi₃, OLi₄, NLi₅ and CLi₆ adsorbed on h-BN through ab initio molecular dynamics (AIMD) simulations at 100, 200 and 300 K. The results suggest that the OLi₃ cluster remains strongly bound to the h-BN surface and it does not exhibit much lateral diffusion, while the rest of the physisorbed species exhibit superdiffusive behaviour. Principal component analysis (PCA) reveals that primarily out-of-plane vibrational degrees of freedom and rotation of the cluster, along with buckling of h-BN, are major contributors to the dynamics of the concerned species. The computed velocity autocorrelation function and the corresponding power spectra provide additional insights into the concerned dynamics.