Markovian dissipative coarse grained molecular dynamics for a simple 2D graphene model

Area of Science:

• Materials Science
• Computational Physics
• Nanotechnology

Background:

• Coarse-grained molecular dynamics (CGMD) is crucial for simulating large-scale material behavior.
• Existing CGMD models for graphene often neglect dissipative effects or lack accuracy in dynamic correlations.
• Understanding graphene's mechanical properties at various scales requires robust computational models.

Purpose of the Study:

• To develop a novel coarse-grained model for graphene mechanics that explicitly includes dissipative effects.
• To investigate the dynamic behavior and non-Markovian characteristics of graphene using the new CGMD model.
• To compare the accuracy and dissipative properties of the new model against traditional center of mass (COM) based CG procedures.

Main Methods:

• Finite-element coarse-grained molecular dynamics (CGMD) applied to a 2D atomistic graphene model.
• Utilizing the Mori-projection operator formalism to derive and incorporate dissipative terms.
• Analysis of nodal momenta and momentum correlation functions to identify non-Markovian behavior.

Main Results:

• A new CGMD model for graphene mechanics accounting for dissipative effects was successfully formulated.
• The model demonstrates accurate reproduction of short-time momentum correlation functions and exhibits less dissipation than COM-CG methods.
• Non-Markovian dynamics were observed in CGMD nodal momenta due to effective high-frequency mode suppression.

Conclusions:

• The developed CGMD model provides a more accurate representation of graphene's short-time dynamics and dissipative behavior.
• The model's ability to capture non-Markovian characteristics is superior to COM-based methods.
• This work enables the development of CGMD models for accurate long-time simulations of macroscopic normal modes in graphene.