Analisys of the mechanical characteristics of bilayer graphene containing covalent bonds between the layers

Abstract

In this project, we propose to deepen studies initiated in our group about the influence of defects that induce the formation of covalent bonds in bilayer graphene. In a previous work, developed with the participation of another IC student funded by Fapesp, we showed that the occurrence of such defects explains a splitting in the XPS signal of bilayer graphene as the concentration of nitrogen incorporated increases, explaining experimental results obtained by a collaborating group. In the present project we propose to simulate how these bonds between the layers affect the resistance of the system to compression, distention and shear stress, with and without the presence of these defects. These properties shall be measured experimentally by partner groups through Raman spectroscopy. Given recent reports about the extraordinary effects that relative rotation of the graphene sheets induce, we plan to verify how the presence of these defects affect the resistance of these layers to rotation stress. These analyses will be performed mostly with classical simulations using parametrized potentials, readily available for the elements under consideration. The student shall also perform parameter free quantum simulations for the pristine system to validate classical results. The student has been working on this project for three months already. She has already studied electronic structure of matter as well as specialized papers related to the theme. Giovanna wrote the introduction to this project, with little interference from the advisor.