Many-body van der Waals interactions in multilayer structures studied by atomic force microscopy
Xiao Wang, Zepu Kou, Ruixi Qiao, Yuyang Long, Baowen Li, Xuemei Li, Wanlin Guo, Xiaofei Liu, Yin Jun
Abstract
Van der Waals interaction in multilayer structures was predicted to be of many-body character, almost in parallel with the establishment of Lifshitz theory. However, the diminishing interaction between layers separated by a finite-thickness intermediate layer prevents experimental verification of the many-body nature. Here we verify the substrate contribution at the adhesion between the atomic force microscopy tip and the supported graphene, by taking advantage of the atomic-scale proximity of two objects separated by graphene. While the pairwise dispersion theory overestimates the substrate contribution at critical adhesive pressures, the many-body dispersion theory remedies this deficiency, highlighting the non-additivity nature of substrate contribution. The many-body effect is further understood through the energy spectrum of charge density fluctuations. These findings open the door to modulating the van der Waals interaction on two-dimensional material surfaces, which would be relevant to various technologies, including microelectromechanical systems and surface molecular assembly. Many-body van-der-Waals interaction in multilayer structures has long been predicted but is difficult to be observed experimentally. Here the authors verify it in a tip graphene-substrate system benefiting from atomically thin intermediate graphene.