Atomistic potential for graphene and other sp² carbon systems

Area of Science:

• Materials Science
• Computational Chemistry
• Condensed Matter Physics

Background:

• Atomistic potentials are crucial for simulating material properties.
• Existing potentials often struggle with out-of-plane deformations in sp2 carbon systems.
• Graphene and related materials exhibit complex behaviors under deformation.

Purpose of the Study:

• To develop a simple yet accurate torsional force field for sp2 carbon.
• To extend existing in-plane potentials for out-of-plane deformations.
• To enable efficient large-scale atomistic simulations of carbon materials.

Main Methods:

• Augmenting a previous in-plane potential with a new torsional force field.
• Fitting the force field to density-functional-theory (DFT) calculation data.
• Validating the potential against known properties of fullerenes, carbon nanotubes, and graphene.

Main Results:

• The proposed potential accurately reproduces characteristic properties of fullerenes and carbon nanotubes.
• It precisely models the out-of-plane acoustic and optical phonon modes of graphene.
• All phonon modes up to 1000 cm-1 in graphene are accurately reproduced.

Conclusions:

• The developed torsional force field significantly improves the simulation of out-of-plane deformations in sp2 carbon materials.
• The potential offers a balance of simplicity, accuracy, and efficiency for large-scale simulations.
• This work provides a valuable tool for understanding the mechanical and vibrational properties of graphene-based systems.