Friction Modulation via Photoexcitation in Two-Dimensional Materials

Area of Science:

• Materials Science
• Condensed Matter Physics
• Tribology

Background:

• Bilayered black phosphorus is a 2D semiconductor with van der Waals interactions.
• Understanding friction in 2D materials is crucial for nanoscale device applications.

Purpose of the Study:

• To investigate the coupling between photoexcitation and friction in bilayered black phosphorus.
• To quantify the impact of photoexcitation on interlayer sliding and friction.

Main Methods:

• Density functional theory (DFT) calculations.
• Prandtl-Tomlinson model for friction analysis.
• Born-Oppenheimer approximation for theoretical insights.

Main Results:

• Photoexcitation reduces the energy barrier for interlayer sliding by 13%.
• Critical force for stick-slip transitions decreases by up to 4.7%.
• Frictional anisotropy can be eliminated at doubled carrier densities.

Conclusions:

• Photoexcitation-friction coupling is demonstrated in bilayered black phosphorus.
• This coupling effect is potentially universal for van der Waals crystals with specific electronic properties.