The interaction of an atomic force microscope tip with a nano-object: a model for determining the lateral force

Area of Science:

• Nanoscience and Nanotechnology
• Materials Science
• Surface Physics

Background:

• Atomic Force Microscopy (AFM) is crucial for nanoscale imaging and manipulation.
• Understanding tip-sample interactions is vital for precise control of nano-objects.
• Existing models may not fully capture lateral forces during manipulation without feedback.

Purpose of the Study:

• To calculate the lateral force interaction between an AFM tip and a nano-object during manipulation.
• To investigate the influence of material parameters, contact mechanics models (JKR, DMT), and nano-object shape on lateral forces.
• To apply the calculation to a specific experimental system: cadmium selenide nanorods on graphite.

Main Methods:

• Utilized Hamaker equations for non-contact force calculations.
• Employed Johnson, Kendall and Roberts (JKR) and Derjaguin, Muller and Toporov (DMT) formalisms for contact force calculations.
• Simulated tip displacement across a nano-object with AFM feedback control disabled.

Main Results:

• Quantified lateral forces during AFM tip-induced nano-object manipulation.
• Demonstrated the significant impact of material properties (e.g., Hamaker coefficients) on lateral forces.
• Showcased the influence of chosen contact mechanics model (JKR vs. DMT) and nano-object geometry on force outcomes.
• Validated the calculation method using a cadmium selenide nanorod on graphite system.

Conclusions:

• Lateral force calculations provide critical insights into AFM manipulation mechanics.
• Material properties and contact theory selection are key determinants of interaction forces.
• The developed model offers a framework for predicting and optimizing nanoscale manipulation strategies.