Dependency of sliding friction for two-dimensional systems on electronegativity

We study the role of electronegativity in sliding friction for five different two dimensional(2D) monolayer systems using density functional theory (DFT) with van der Waals (vdW)corrections. We show that the friction between the commensurate 2D layered systems dependsstrongly on the electronegativity difference of the involved atoms. All the 2D layered structuresexhibit almost the same magnitude of friction force when sliding along the nonpolar path,independent of the material and the surface structures. In contrast, for sliding friction along thepolar path, the friction force obeys a universal linear scaling law as a function of theelectronegativity difference of its constituent atoms. Further analyses demonstrate that atomicdipoles in the 2D monolayers induced by the electronegativity difference enhance the corrugation ofcharge distribution and increase sliding barrier accordingly. Our studies revealthat electronegativity plays an important role in friction of low dimensional systems, and willprovide a strategy for designing nanoscale devices further.Keywords: Electronegativity; Friction; Two-dimensional (2D) monolayer; Density functionaltheory (DFT)