An Atomistic-Based Nonlinear Plate Theory for Hexagonal Boron Nitride.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Hexagonal boron nitride (h-BN) is a 2D nanomaterial with unique mechanical properties.
• Classical plate theories often fail to capture the atomic-level mechanics of 2D materials.
• Understanding the atomic source of h-BN's deformation resistance is crucial for its applications.

Purpose of the Study:

• To develop a finite-deformation plate theory for single-layer h-BN based on the DREIDING force field.
• To elucidate the atomic origins of h-BN's mechanical properties and elastic rigidities.
• To establish a foundation for applying classical plate theories to h-BN and similar 2D nanostructures.

Main Methods:

• Continuity of the DREIDING force field.
• Development of a novel finite-deformation plate theory for single-layer h-BN.
• Comparison of theoretical mechanical parameters with atomic calculations.

Main Results:

• The new theory demonstrates independence between in-plane and out-of-plane mechanical parameters of h-BN.
• Identified atomic contributions to elastic rigidities: bond stretching/bending for in-plane, inversion/torsion for bending, and torsion for Gaussian rigidity.
• Validated theoretical parameters against atomic calculations.
• Determined the necessity of two four-body terms in the DREIDING force field for accurate h-BN modeling.

Conclusions:

• The proposed finite-deformation plate theory accurately models h-BN's mechanical behavior at the atomic level.
• The theory provides a framework for understanding and predicting the mechanical response of 2D materials.
• This approach offers a heuristic method for modeling the mechanical properties of other two-dimensional nanostructures.