First-principles study on the reconstruction induced by the adsorption of C60 on Pt(111)

Abstract

The adsorption of C60 on a Pt(111) surface and the origins of the √13 × √13R13.9° or 2√3 × 2√3R30° reconstruction of the C60/Pt(111) system have been investigated by means of first-principles calculations. In agreement with the experimental observations, our calculations reveal that the C60 molecule binds covalently on the Pt(111) surface. The C60 molecule adsorbs on the Pt(111) surface with the center of a hexagonal ring located on top of a surface Pt atom. The surface Pt atom can be removed easily, forming a Pt vacancy upon the adsorption of C60 molecule. Our calculation results show that the strong covalent bonds between C60 and the Pt(111) surface and the formation of adatom-vacancy pairs in the C60/Pt(111) system may be the main driving forces promoting the substrate reconstructing pattern observed in experiments.

Vacancy formation on C60/Pt (111): unraveling the complex atomistic mechanism

“…This structure is 0.69 eV more stable than the hex0 configuration. This combination of vacancy and hcp adatom has been proposed before in [7] but the calculation was performed on a 4 × 4 unit cell, not on the real (√13 × √13) R13.9°periodicity, resulting in an energy gain of 0.32 eV. Finally, we have to stress that both the hex0-vac and the adatom-vacancy configurations are stable, so there is an energy barrier for the migration of the vacancy from the side to the position right below the fullerene in the presence of the Pt adatom.…”

“…In this way, we have identified the two lowest energy configurations which will be referred to as dimer30 and hex0. They correspond to (i) the molecule sitting on a 6 : 6 dimer bridging between two Pt-hexagons at 30°with respect to the [1][2][3][4][5][6][7][8][9][10] surface direction for dimer30, and to (ii) the fullerene oriented on a carbon hexagon on top of a Pt hexagon on the surface for hex0 (see figure 6). These two configurations have been recalculated with VASP and they provide the basis for the rest of our theoretical study.…”

“…Reference [7] suggested that the Pt atom right below the fullerene could directly migrate to the surface and form an adatom-vacancy pair. The bulk selfdiffusion of a Pt atom is a costly process in terms of energy.…”

“…Based on calculations for the (2√3 × 2√3)R30°case and the theoretical analysis of the low energy electron diffraction (LEED) patterns, they confirm that a single vacancy is present in this system, as opposed to the seven-atom hole stable in the C 60 /Cu(111) case, and that the local bonding configuration is the same for both reconstructions. Recently, Huang et al [7] has revisited this problem with a gradient-corrected generalized gradient approximation (GGA) functional. He assumed a hexagonal orientation for the adsorbed fullerene and studied the bonding configuration with and without a single atom vacancy.…”

“…There is an extended bibliography on thin films of C 60 on many different single crystal metal substrates as Pt [4][5][6][7][8][9][10], Al [11,12], Cu [13][14][15][16][17][18], Au [19][20][21][22][23][24][25][26][27][28] and Ag [29][30][31][32][33][34] or even on graphene [35], among many others. On some metals, when deposited at room temperature (RT), C 60 interacts with both the metallic surface and the surrounding molecules by van der Waals (vdW) interactions.…”