Calculating the free energy of 2D materials on substrates

TL;DR

This paper introduces a fast and accurate method for calculating the free energy of 2D materials on substrates, demonstrated on graphene and { extgamma}-graphyne on copper, with potential applications in material growth analysis.

Contribution

A novel computational approach that accelerates free energy calculations for 2D materials on substrates by over three orders of magnitude with high precision.

Findings

Method is at least 1000 times faster than existing algorithms.

Achieves internal energy calculation accuracy of 0.03% from 100 to 1300K.

Free energy of graphene on Cu or Ni surfaces is lower than that of { extgamma}-graphyne, consistent with growth ease.

Abstract

A method was developed to calculate the free energy of 2D materials on substrates and was demonstrated by the system of graphene and {\gamma}-graphyne on copper substrate. The method works at least 3 orders faster than state-of-the-art algorithms, and the accuracy was tested by molecular dynamics simulations, showing that the precision for calculations of the internal energy achieves up to 0.03% in a temperature range from 100 to 1300K. As expected, the calculated the free energy of a graphene sheet on Cu (111) or Ni (111) surface in a temperature range up to 3000K is always smaller than the one of a {\gamma}-graphyne sheet with the same number of C atoms, which is consistent with the fact that growth of graphene on the substrates is much easier than {\gamma}-graphyne.