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AB initio investigation of the nanotribological properties of the h-BN/h-BN and the h-BN/Au(111) interfaces

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2019
Baksi, Merve
As the size of the systems reduces due to the advances in fabrication techniques, materials properties that apply at macroscopic scale start to lose their validity. As a reflection of this, friction at the atomic scale does not obey the macroscopic Da Vinci-Amontons’ description. Each interface that experiences losses due to friction therefore requires a separate examination. A particularly intensely studied class of materials from a nanotribological point of view is the two-dimensional networks. In addition to the interface of two-dimensional materials with themselves, the interface between these materials and bulk surfaces are of interest. In this thesis, we examined the nanotribological properties of the h-BN/h-BN (hexagonal boron nitride), and h- BN/Au(111) surfaces using Density Functional Theory (DFT). h-BN/Au(111) interface is particularly relevant for modelling atomic force microscopy (AFM) and friction force microscopy (FFM) experiments since it is expected to reveal superlubric behaviour. We identify and discuss trends in the behavior of the friction force as a function of vertical load for experimentally feasible contact area. Moreover, in order to understand the edge effects of the interface, the interaction between small Au clusters and the h-BN network is also investigated.