Superlubricity of two-dimensional fluorographene/MoS2 heterostructure: a first-principles study

Area of Science:

• Materials Science
• Condensed Matter Physics
• Tribology

Background:

• Atomic-scale friction is crucial for understanding material wear and performance.
• Fluorographene (FG) and Molybdenum Disulfide (MoS2) are 2D materials with unique properties.
• Heterostructures of 2D materials offer tunable electronic and mechanical characteristics.

Purpose of the Study:

• To investigate the atomic-scale friction of the FG/MoS2 heterostructure.
• To understand the mechanisms behind superlubricity in this system.
• To explore the relationship between Moiré patterns, lattice mismatch, and friction.

Main Methods:

• First-principles calculations were employed.
• Analysis of the potential energy surface was performed.
• Interlayer shear strength was computed and compared.

Main Results:

• The FG/MoS2 heterostructure exhibits an ultrasmooth potential energy surface.
• Interlayer shear strength is reduced by two orders of magnitude compared to pristine bilayers.
• Superlubricity is achieved in the FG/MoS2 heterostructure.
• The emergence of Moiré patterns due to lattice mismatch is key to superlubricity.

Conclusions:

• The FG/MoS2 heterostructure enters the superlubricity regime due to lattice mismatch and Moiré pattern formation.
• The size dependency of superlubricity is linked to Moiré pattern formation and lattice mismatch ratio.
• This study provides insights into designing 2D heterostructures for ultra-low friction applications.