Metal intercalation-induced selective adatom mass transport on graphene
Recent experiments indicate that metal intercalation is a very effective method to manipulate the graphene-adatom interaction and control metal nanostructure formation on graphene. A key question is mass transport, i.e., how atoms deposited uniformly on graphene populate different areas depending on the local intercalation. Using first-principles calculations, we show that partially intercalated graphene, with a mixture of intercalated and pristine areas, can induce an alternating electric field because of the spatial variations in electron doping, and thus, an oscillatory electrostatic potential. This alternating field can change normal stochastic adatom diffusion to biased diffusion, leading to selective mass transport and consequent nucleation, on either the intercalated or pristine areas, depending on the charge state of the adatoms.
Keywordsgraphene intercalation electrostatic potential selective adsorption first-principle calculation
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- The interaction energy between the two adatoms on graphene is defined as Einter(r)= E a2(r)-2E a1. Here, E a2(r) is the adsorption energy of two Eu adatoms on graphene at a separation r, and Ea1 is the adsorption energy of a single Eu adatom. The E a2(r) and Ea1 are obtained by first-principles DFT calculations using a 10 - 10 graphene supercell with one or two adatoms and periodic boundary conditions. The interaction between Eu–Eu adatoms is attractive at small separations (less than 5.0 Å) but becomes repulsive at the distances larger than 6.0 Å with maximum repulsion of 0.24 eV.Google Scholar