Análisis y validación de un modelo molecular de grafeno utilizando potencial Tersoff polarizable mediante simulaciones de dinámica molecular.
Loading...
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
El grafeno es un material bidimensional que ha ganado relevancia en la investigación actual debido a sus propiedades únicas y variadas aplicaciones. Dado que el grafeno es caro y difícil de manejar experimentalmente, las simulaciones computacionales son cruciales para recrear su comportamiento y evaluar sus aplicaciones. Este estudio busca verificar si la adición de efectos de polarización a un potencial tipo Tersoff permite reproducir con suficiente precisión las propiedades elásticas al modelar hojas de grafeno mediante dinámica molecular. Luego, el objetivo principal consiste en analizar y validar un modelo molecular de grafeno utilizando una combinación entre potencial Tersoff y el modelo de osciladores de Drude, resultando en un potencial Tersoff polarizable. Para ello, se generaron sistemas polarizables y no polarizables de grafeno suspendido y multiláminas, que se sometieron a microdesplazamientos en simulaciones de dinámica molecular gracias al software LAMMPS. A partir de estas simulaciones, se extrajeron los datos de tensor de esfuerzos y deformación y se determinaron las propiedades elásticas de cada sistema. Como resultado, para el grafeno polarizable se obtuvo un módulo elástico de 0.950 TPa y un coeficiente de Poisson de 0.070, el modelo también muestra un comportamiento frágil y un esfuerzo de ruptura menor que los obtenibles en sistemas no polarizables. Finalmente, se compararon las propiedades obtenidas de este modelo con resultados experimentales reportados por otros autores. A partir de este análisis comparativo se concluye que las hojas de grafeno parametrizadas mediante potencial Tersoff polarizado es mas flexible al ser sometido a deformaciones dentro de la zona elástica, pero frágil e inestable para mayores deformaciones.
Graphene is a two-dimensional material that has gained relevance in current research due to its unique properties and various applications. Since graphene is expensive and difficult to handle experimentally, computational simulations are crucial to recreate its behavior and evaluate its applications. This study aims to verify whether the addition of polarization effects to a Tersoff-type potential can accurately reproduce the elastic properties when modeling graphene sheets using molecular dynamics. The main objective is to analyze and validate a molecular model of graphene by using a combination of the Tersoff potential and the Drude oscillator model, resulting in a polarizable Tersoff potential. To this end, polarizable and non-polarizable suspended graphene and multilayer systems were generated and subjected to micro-displacements in molecular dynamics simulations performed with LAMMPS. From these simulations, stress and strain tensor data were extracted, and the elastic properties of each system were determined. As a result, for polarizable graphene, an elastic modulus of 0.950 TPa and a Poisson’s ratio of 0.070 were obtained, with the model also exhibiting a brittle behavior and a lower breaking stress than in non-polarizable systems. Finally, the properties obtained from this model were compared with experimental results reported by other authors. Based on this comparative analysis, it is concluded that graphene sheets parameterized with the polarizable Tersoff potential are more flexible under elastic strain but brittle and unstable under greater deformations.
Graphene is a two-dimensional material that has gained relevance in current research due to its unique properties and various applications. Since graphene is expensive and difficult to handle experimentally, computational simulations are crucial to recreate its behavior and evaluate its applications. This study aims to verify whether the addition of polarization effects to a Tersoff-type potential can accurately reproduce the elastic properties when modeling graphene sheets using molecular dynamics. The main objective is to analyze and validate a molecular model of graphene by using a combination of the Tersoff potential and the Drude oscillator model, resulting in a polarizable Tersoff potential. To this end, polarizable and non-polarizable suspended graphene and multilayer systems were generated and subjected to micro-displacements in molecular dynamics simulations performed with LAMMPS. From these simulations, stress and strain tensor data were extracted, and the elastic properties of each system were determined. As a result, for polarizable graphene, an elastic modulus of 0.950 TPa and a Poisson’s ratio of 0.070 were obtained, with the model also exhibiting a brittle behavior and a lower breaking stress than in non-polarizable systems. Finally, the properties obtained from this model were compared with experimental results reported by other authors. Based on this comparative analysis, it is concluded that graphene sheets parameterized with the polarizable Tersoff potential are more flexible under elastic strain but brittle and unstable under greater deformations.
Description
Tesis presentada para optar al grado de Magíster en Ciencias de la Ingeniería con mención en Ingeniería Mecánica
Keywords
Grafeno, Dinámica molecular