Registry-Dependent Potential for Interfaces of Gold with Graphitic Systems.

Wengen Ouyang,Roberto Guerra,Oded Hod

doi:10.1021/acs.jctc.1c00622

Wengen Ouyang, Roberto Guerra + Show 1 more

Open Access

https://doi.org/10.1021/acs.jctc.1c00622

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Abstract

We present a semi-anisotropic interfacial potential (SAIP) designed to classically describe the interaction between gold and two-dimensional (2D) carbon allotropes such as graphene, fullerenes, or hydrocarbon molecules. The potential is able to accurately reproduce dispersion-corrected density functional theory (DFT+D3) calculations performed over selected configurations: a flat graphene sheet, a benzene molecule, and a C60 fullerene, physisorbed on the Au(111) surface. The effects of bending and hydrogen passivation on the potential terms are discussed. The presented SAIP provides a noticeable improvement in the state-of-the-art description of Au–C interfaces. Furthermore, its functional form is suitable to describe the interfacial interaction between other 2D and bulk materials.

Highlights

The reproducibility of the phenomena emerging at the interface between two bodies in contact is often limited by the availability of clean and well-controllable surfaces
We note that the negative sign in the C parameter can be attributed to the fact that the atop position of an Au atom on graphene is energetically favorable with respect to the hollow position,[18,19] where the Au atom resides over the graphene hexagon center
Note that the DFT calculations show a similar adhesion energy (AE), regardless of the number of gold layers, while the semi-anisotropic interfacial potential (SAIP) predicts a reduced adhesion in the case of a single gold layer. We associate the former with the fact that decreasing the number of layers reduces the adhesive interactions, but at the same time the undercoordinated Au surface becomes more chemically reactive. This is related to the known increased atomic density of gold surfaces with respect to bulk.[46−49] Such compensation yields an almost unchanged AE value, just slightly reduced with respect to the bilayer case

Summary

INTRODUCTION

The reproducibility of the phenomena emerging at the interface between two bodies in contact is often limited by the availability of clean and well-controllable surfaces. Torres et al measured an adhesion energy (AE) Ea = 7687.1 mJ/m2 in the case of graphene-covered gold nanoparticles,[27] while a pull-off force of Fa = 45.7 ± 5.1 nN was measured by Li et al for gold-coated atomic force microscopy probes forming a ∼200 nm[2] contact with a graphite substrate.[23] Other experiments provide only indirect information based on empirically fitted models or simulations.[6,7,9,28] The comparison with experiments is further complicated by the presence of surface reconstruction at the gold surface, usually neglected in first-principles calculations due to the large supercell size required to encompass its long (∼6.3 nm) wavelength Leaving out such reconstruction effects potentially overestimates the computed interaction energies, but in most cases, this approximation yields only minor structural modifications in the model systems.[29]. The SAIP formulation provides a general tool for describing interfaces formed between two-dimensional (2D) materials and bulk solids

POTENTIAL DESCRIPTION

MODEL SYSTEMS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES