Effect of surface termination on superlow friction of diamond film: A theoretical study

We have applied molecular dynamics simulation and density functional theory calculations to analyze the effects of H and OH terminations on the frictional properties of diamond films at the atomistic and electronic levels. Molecular dynamics simulations were carried out for H-, OH-, and non-terminated diamond surfaces against an iron surface. Results of molecular dynamics simulations show that the frictional force is clearly decreased by the H or OH termination on the diamond surfaces. Moreover, results of density functional calculations show that a covalent bond is formed between Fe and C, while H- or OH-terminated diamond surfaces interact repulsively with an iron surface owing to antibonding interactions. We concluded that this interaction change between iron and diamond surfaces is the major contributing factor for achieving a low friction in H- or OH-terminated diamond.