Density Functional Theory Calculations of Graphene-Substrate Systems

Since graphene is supported by a material in most applications, understanding the interactions between graphene and different substrates is crucial for determining their effects on graphene’s electronic properties. For accurate modeling of such systems, density functional theory (DFT) using functionals that include dispersion, or van der Waals (vdW), interactions is necessary to gain insights into these effects. In this work, we use the SCAN functional as well as the PBE functional with various vdW corrections to study graphene on Ni and Au, among other substrates. Also, to study the sensitivity of the Fermi level, an external electric field will be applied to the system. By determining the graphene adsorption type, distance, and energy for known graphene-substrate geometries, we evaluate the different substrate effects. Also considered will be the adsorption of molecules on various graphene-substrate combinations. These results are compared to experiments and theoretical calculations with different vdW functionals to assess the validity of using the SCAN functional in graphene-substrate systems.