Control of interlayer friction in two-dimensional ferromagnetic CrBr₃

Area of Science:

• Materials Science
• Nanotechnology
• Tribology

Background:

• Two-dimensional (2D) magnetic materials offer novel possibilities for nanoscale lubrication.
• Investigating interfacial magnetic coupling is crucial for understanding friction in these materials.

Purpose of the Study:

• To explore the tribological and interfacial properties of bilayer CrBr3 using first-principles calculations.
• To analyze the impact of external factors like load, strain, and doping on magnetic coupling and friction.

Main Methods:

• First-principles calculations were employed to simulate bilayer CrBr3.
• Interfacial properties, magnetic coupling, and energy barriers were computationally investigated.

Main Results:

• A conversion between ferromagnetic (FM) and antiferromagnetic (AFM) interlayer magnetic couplings was identified, reducing sliding energy barriers.
• Bilayer CrBr3 demonstrated a lower sliding energy barrier, indicating reduced friction and enhanced lubricating potential.
• Optimal conditions for reduced friction include specific normal loads (0.5-1.0 eV Å⁻¹), compressive biaxial strain (0% to -5%), and carrier doping (-0.2 to 0.2 e f.u.⁻¹).
• Biaxial strain was found to modulate interlayer electron distribution, influencing interactions and friction.

Conclusions:

• 2D ferromagnetic CrBr3 exhibits promising lubricating properties for nanoscale applications.
• External stimuli like load, strain, and doping can be tuned to optimize friction reduction.
• Understanding the interplay between magnetic coupling and interfacial properties is key for designing advanced solid lubricants.