title: Communication: Surface-to-bulk diffusion of isolated versus interacting C atoms in Ni(111) and Cu(111) substrates: A first principle investigation.
abstract: Using first principle calculations, we study the surface-to-bulk diffusion of C atoms in Ni(111) and Cu(111) substrates, and compare the barrier energies associated with the diffusion of an isolated C atom versus multiple interacting C atoms. We find that the preferential Ni-C bonding over C-C bonding induces a repulsive interaction between C atoms located at diagonal octahedral voids in Ni substrates. This C-C interaction accelerates C atom diffusion in Ni with a reduced barrier energy of ∼1 eV, compared to ∼1.4-1.6 eV for the diffusion of isolated C atoms. The diffusion barrier energy of isolated C atoms in Cu is lower than in Ni. However, bulk diffusion of interacting C atoms in Cu is not possible due to the preferential C-C bonding over C-Cu bonding, which results in C-C dimer pair formation near the surface. The dramatically different C-C interaction effects within the different substrates explain the contrasting growth mechanisms of graphene on Ni(111) and Cu(111) during chemical vapor deposition.
authors: Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors: Abhilash
authors: A
authors: Harpale
authors: Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors: Marco
authors: M
authors: Panesi
authors: Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors: Huck Beng
authors: HB
authors: Chew