First-Principles Study Of V、Cr、Co Doped In Graphene

Graphene is one of the most popular new materials scientists studied because of its unique and excellent electrical, mechanical and thermal properties in recent years. These excellent properties of graphene make it can be applied in many fields, such as the production of semiconductor devices, super capacitor, hydrogen storage and high frequency circuit, etc., Graphene is zero band gap semiconductor make it cannot be applied in making magnetic devices, such as spin semiconductor devices. Scientists found that defects and doping metal can make graphene applicated in more fields.In Chapter 1, the electronic structure,properties(mechanical properties, optical properties, anomalous quantum hall effect, etc.), synthesis(mechanical exfoliation, chemical vapor deposition, etc.) of graphene are introduced, in the end of this section, the purpose of this article are described.In Chapter 2, we give a brief introduction to the many-body theory, the first-principles method based on density functional theory, some concepts of the density functional theory, such as theory of quantum many-body systems, Hohenberg-Kohn theorem, etc. Pseudopotential and projector augmented wave are introduced,too. Finally we introduced the calculation software(VASP) in our study about the nine graphene doping structures.In Chapter 3, in order to further study how impurities influence the properties of graphene, especially magnetism, We constructed three kinds of doping structures(Replace one carbon atom, in the same plane and not in the same plane with the six-member ring). We calculated and analyzed the magnetic performance, band structure, spin polarization and electron density of states of nine doping structures by VASP which is based on Density Functional Theory, and the pseudopotential Linearized Augmented Plane Wave method.