Atomic-scale friction along various scan paths starting at different points

Abstract Atomic-scale friction has been investigated for a long time which is vital in reducing energy dissipation in MEMS, and most of the factors which can affect friction such as velocity, temperature, normal force, angle, and so on, have been applied to study friction. But the starting points of...
Ausführliche Beschreibung

Abstract Atomic-scale friction has been investigated for a long time which is vital in reducing energy dissipation in MEMS, and most of the factors which can affect friction such as velocity, temperature, normal force, angle, and so on, have been applied to study friction. But the starting points of the scan path of the tip are not discussed very concretely. In this essay, molecular simulation and numerical analysis are used to investigate how the starting points of path and other elements influence friction. The result of molecular simulation is explained by the two-dimensional Prandtl–Tomlinson model. The moving path of the tip affected by angle, initial positions, and temperature, is plotted on the interaction potential energy surface of silicon, so it is easy to know the way that causes the change of lateral force from the figure. Conclusions are drawn as follows: Lateral force becomes the smallest when the tip moves at the angle of 45° because its path do not need to be corrected to the moving direction as set before, and energy barrier of the path at 45° is the lowest in all of the angles. All of the scanning lines that start at different initial locations are centralized to a narrow band, lateral force reaches its minimum when it moves in the line beginning at one-quarter or three-quarters of lattice whose average energy difference of each step is the least rather than in any other starting positions. Temperature can assist the tip to reside in a larger area and move more tortuous to surmount the energy peak instead of reducing energy barrier of friction which is different from traditional explanation. Ausführliche Beschreibung