Rotation, translation, charge transfer, and electronic structure ofC60on Cu(111) surface

Abstract

The energetics and electronic structure of a C 60 monolayer on Cu͑111͒ surfaces have been investigated thoroughly via large-scale first-principles density functional theory. The calculated adsorption site and orientation of the molecule, and the work function are in excellent agreement with experimental observations. We find that the translational motion of C 60 across Cu-Cu bonds can be barrierless, while a 360°, on-site rotational motion is subject to a barrier of 0.3 eV. A close to 0.8e Ϫ charge transfer per molecule from the surface to the C 60 monolayer is determined, which provides important insights into a number of experimental measurements. Our analysis also indicates that the transferred electrons are localized in a plane between the molecule and surface, and that the bands near the Fermi level are highly hybrid between the surface and the molecule, reflecting a strong metal-fullerene coupling. Furthermore, an analysis of the dipole moment clarifies the puzzling phenomenon regarding the work function.

Time-resolved photoelectron spectroscopy of low-energy excitations of 4×4 C60/Cu(111)

“…Both spectra are in agreement with a calculation by Wang and Cheng [73] for the (4x4) superstructure. In agreement with Tsuei and coworkers [70,71] the Shockley surface state shows dispersion, but in the present investigation appears enhanced compared to the Cu 3d bands at lower energies, which might be due to the different probe photon energies.…”

“…Integration of the charge redistribution yields the net charge transfer into C 60 as a function of the definition of the precise position of the interface between Cu(111) and C 60 . The range of values of this integral explains the range of the reported charge transfers which is 0.8 [73] to 2.0 [74] electrons per C 60 molecule. Eberhardt and coworkers [38] observed the LUMO+1, the LUMO and the singlet exciton in a 3 nm thick fullerite film on Ag(100).…”

“…In 2004 Louie and coworkers [72] calculated by means of DFT the electron redistribution for the adsorption of a single C 60 molecule on Au(111) and on Ag (100). Similarly Wang and Cheng [73] calculated the electron redistribution for the adsorption of one ML on Cu (111). The charge redistribution integrated in planes parallel to the surface is a function of the distance between the chosen plane and the position of the metal nuclei.…”

Jahn–Teller Effects in Molecules on Surfaces with Specific Application to C60

“…(6) becomes E crit ∼ 32.0 kT .) A recent density functional theory (DFT) study [14] of C 60 on Cu(111) indicates that the adsorbate is most energetically stable when localized over a hcp site (although the fcc site is only 20 meV higher in energy). A barrier to rotation of 300 meV is predicted.…”

C60-induced Devil's Staircase transformation on a Pb/Si(111) wetting layer

“…45,46 . DFT-LDA calculations have been shown to describe well the C 60 /metal interfaces, to explain successfully the puzzle in work function change on noble metal surfaces after C 60 adsorption, 32,33 and to predict the energetics of the surface reconstructions induced by C 60 , 20,21 and even the different orientations of C 60 at the single vacancy on Ag(111) and Au(111) . 25 To estimate the van der Waals (vdW) interaction in the system 38,47 , DF1-optPBE has been used to check key results.…”