Potential energy surface for graphene on graphene:Ab initioderivation, analytical description, and microscopic interpretation

Abstract

We derive an analytical expression that describes the interaction energy between two graphene layers identically oriented as a function of the relative lateral and vertical positions, in excellent agreement with first principles calculations. Thanks to its formal simplicity, the proposed model allows for an immediate interpretation of the interactions, in particular of the potential corrugation. This last quantity plays a crucial role in determining the intrinsic resistance to interlayer sliding and its increase upon compression influences the frictional behavior under load. We show that, for these weakly adherent layers, the corrugation possesses the same nature and z dependence of Pauli repulsion. We investigate the microscopic origin of these phenomena by analyzing the electronic charge distribution: We observe a pressure-induced charge transfer from the interlayer region toward the near-layer regions, with a much more consistent depletion of charge occurring for the AA stacking than for the AB stacking of the two layers.

Interlayer interaction and related properties of bilayer hexagonal boron nitride: ab initio study

“…Therefore small deviations in the equilibrium interlayer distance predicted by different DFT methods result in significant errors in the properties related to interaction and relative motion of the layers. 55,59,60,86 On the other hand, inclusion of vdW interactions almost does not affect the potential energy surface at a given interlayer distance. 54,55,59,60,66 Thus it is reasonable to study the potential energy surface at the equilibrium interlayer distance known from the experiments rather than rely on the values provided by the DFT methods.…”

“…Though significant efforts have been made recently to improve description of the long-range vdW interactions in DFT, 67,72,84,85 available DFT methods still fail to predict the equilibrium distance between 2D layers with sufficient accuracy. 55,59,60,86 However, the magnitude of corrugations of the potential energy surface 59,60,64 and barriers to relative motion of the layers 60 depend exponentially on the interlayer distance. Therefore small deviations in the equilibrium interlayer distance predicted by different DFT methods result in significant errors in the properties related to interaction and relative motion of the layers.…”

“…66 , DFT-D calculations for polycyclic aromatic hydrocarbons adsorbed on graphene), 2.6 meV/atom (Ref. 59 ), 2.07 meV/atom (Ref. 60 , DFT-D calculations for bilayer graphene), 1 meV/atom (Ref.…”

“…64 , DFT calculations for graphite within local density approximation (LDA) and generalized gradient approximation (GGA)), 2.6 meV/atom (Ref. 59 ), 1.82 meV/atom (Ref. 65 , LDA calculations for bilayer graphene), 1 − 1.5 meV/atom (Ref.…”

“…60 , DFT-D calculations for bilayer graphene), 1 meV/atom (Ref. 59 ), 1.92 meV/atom (Ref. 60 , calculations for bilayer graphene using the vdW-DF functional 67 ).…”