Strain-tunable van der Waals interactions in few-layer black phosphorus.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Interlayer interactions, or van der Waals (vdWs) interactions, are crucial for the properties of 2D materials.
• Manipulating these interactions allows for tailoring material characteristics.

Purpose of the Study:

• To investigate the effect of in-plane biaxial strain on vdWs interactions in few-layer black phosphorus.
• To explore the potential for strain engineering to redefine material properties.

Main Methods:

• Utilized infrared spectroscopy to probe vdWs interactions in 2-10 layer black phosphorus under strain.
• Employed density functional theory (DFT) calculations to support experimental observations.

Main Results:

• Demonstrated that in-plane tensile strain effectively tunes vdWs interactions.
• Observed a weakening of interlayer coupling with tensile strain, despite vertical shrinkage due to the Poisson effect.
• DFT calculations confirmed the experimental findings and highlighted the role of the puckered lattice structure.

Conclusions:

• In-plane biaxial strain is an effective method for tuning vdWs interactions in 2D materials.
• The observed weakening of interlayer coupling under tensile strain challenges conventional intuition.
• vdWs interactions are significantly influenced by external physical perturbations in 2D materials.