Molecular dynamics study of the robust superlubricity in penta-graphene van der Waals layered structures

Since Penta-Graphene (PG), a two-dimensional (2D) carbon allotrope exclusively composed of five-membered rings, was proposed, its electronic structure, thermal conductivity, and other properties have been extensively investigated based on density functional theory (DFT) and molecular dynamics (MD) methods, but its interlayer frictional properties have not been reported. This work is based on the molecular dynamics (MD) simulation method to study the phenomenon of interlayer robust structural superlubricity of Penta-Graphene van der Waals layered structures, including Penta-Graphene/Penta-Graphene (PG/PG), Penta-Graphene/Graphene (PG/G), and Penta-Graphene/MoS2 (PG/MoS2). Furthermore, we demonstrate the dominance of edge effects in the friction process. Based on our statistical results, it is found that the frictional contribution per atom in the edge region is at least one order of magnitude greater than the contribution of the in-plane atoms. In addition, the factors affecting the frictional properties of the interlayer are investigated, and the associated physical mechanisms of friction are discussed. This work may apply to other pentagonal heterostructure systems, which could help in the future exploration of novel structural superlubricity systems. Meanwhile, this work not only effectively increases the variety of structural superlubricity materials but also expands the application of two-dimensional pentagonal materials in the field of nanofriction.