Universal description of potential energy surface of interlayer interaction in two-dimensional materials by first spatial Fourier harmonics

TL;DR

This paper demonstrates that the potential energy surface of interlayer interactions in 2D materials can be universally modeled using the first spatial Fourier harmonics, validated for hydrofluorinated graphene bilayers.

Contribution

It extends the universal Fourier harmonic description of interlayer PES to hydrofluorinated graphene, supported by DFT calculations and analytical modeling.

Findings

PES of HFG bilayer is accurately described by first Fourier harmonics with 3% error.

Derived analytical expression matches DFT-calculated PES.

HFG bilayer is stable against HF molecule formation.

Abstract

We propose a hypothesis that the potential energy surface (PES) of interlayer interaction in diverse 2D materials can be universally described by the first spatial Fourier harmonics. This statement (checked previously for the interactions between graphene and hexagonal boron nitride layers in different combinations) is verified in the present paper for the case of hydrofluorinated graphene (HFG) bilayer with hydrogen bonding between fluorine and hydrogen at the interlayer interface. The PES for HFG bilayer is obtained through density functional theory calculations with van der Waals corrections. An analytical expression based on the first Fourier harmonics describing the PES which corresponds to the symmetry of HFG layers is derived. It is found that the calculated PES can be described by the first Fourier harmonics with the accuracy of 3\% relative to the PES corrugation. The shear mode frequency, shear modulus and barrier for relative rotation of the layers to incommensurate states of HFG bilayer are estimated. Additionally it is shown that HFG bilayer is stable relative to the formation of HF molecules as a result of chemical reactions between the layers.