Comparison of performance of van der Waals-corrected exchange-correlation functionals for interlayer interaction in graphene and hexagonal boron nitride

摘要

Exchange-correlation functionals with corrections for van der Waalsinteractions (PBE-D2, PBE-D3, PBE-D3(BJ), PBE-TS, optPBE-vdW and vdW-DF2) aretested for graphene and hexagonal boron nitride, both in the form of bulk andbilayer. The characteristics of the potential energy surface, such as thebarrier to relative sliding of the layers and magnitude of corrugation, andphysically measurable properties associated with relative in-plane andout-of-plane motion of the layers including the shear modulus and modulus foraxial compression, shear mode frequency and frequency of out-of-planevibrations are considered. The PBE-D3(BJ) functional gives the best results forthe stackings of hexagonal boron nitride and graphite that are known to beground-state from the experimental studies. However, it fails to describe theorder of metastable states of boron nitride in energy. The PBE-D3 and vdW-DF2functionals, which reproduce this order correctly, are identified as theoptimal choice for general studies. The vdW-DF2 functional is preferred forevaluation of the modulus for axial compression and frequency of out-of-planevibrations, while the PBE-D3 functional is somewhat more accurate incalculations of the shear modulus and shear mode frequency. The bestdescription of the latter properties, however, is achieved also using thevdW-DF2 functional combined with consideration of the experimental interlayerdistance. In the specific case of graphene, the PBE-D2 functional works verywell and can be further improved by adjustment of the parameters.