Lubricity Characters in van der Waals SnS2/Graphene and SnS2/NbTe2 Ohmic Interface

Exploring the lubricity characters in van der Waals (vdW) interfaces is a hot topic in nanotribology. We study the friction performances for the Ohmic-contacted lattice-matched SnS2/NbTe2 and lattice-mismatched SnS2/graphene vdW systems through DFT simulations. The friction in the lattice-mismatched system is found to be two orders of magnitudes smaller. The weaker interaction between the interface and the smoother condition at the interface in the SnS2/graphene system leads to a smoother potential energy fluctuation, which is responsible for the tiny friction in compared to the SnS2/NbTe2 system. Moreover, the friction coefficients are quite low for the lattice-mismatched bilayer with values of 5.16 × 10–3–6.46 × 10–2 under a load of 3.46 × 10–3 0.15 nN/atom. Our work suggests the SnS2/graphene vdW system is a potential solid lubricant with superlubricity. The lattice-mismatched SnS2/graphene vdW system guarantees a distinctly low friction feature due to the tiny variation of charge density difference