A Critical Assessment of vdW Corrections Methods: A Case Study on Graphene

Abstract

Owing to its unique properties, graphene is among the most studied materials. Literature on mechanical properties of a few-layer-graphene is, however, barely available. In the present contribution, we investigate the compression and tension behaviour of bi- and tri-layer graphene for both stacking orders (A-A and A-B (Bernal)). A key aspect in the investigation of multilayer graphene is an accurate description of long-ranged electronic correlation phenomena between the atomic layers. Van-der-Waals interactions are not tractable within the standard formalism of density functional theory (DFT) and hence are included via corrections. After benchmarking vdW-correction methods against well-known properties of graphite, we examine stacks of up to ten layers of graphene sheets. We investigate their effect on interlayer spacings and out-of-plane stiffness systematically in combination with two different commonly used exchange-correlation functionals.