First-Principles Study Of Carbon Nanomaterials

Nanomaterials in a new generation of nanoscale materials, with a variety of exotic features, showing specific optical, electrical, magnetic, thermal, mechanical, mechan-ical and other physical and chemical properties, which makes nanotechnology rapidly penetrated into different kinds of research fields, attracting many physicists, chemists and materials scientists at home and abroad and also becoming the world’s most popu-lar scientific research hot spots. Physicists interested in nanomaterials because it has a unique electromagnetic properties, chemists because of its chemical activity and poten-tial application value, materials scientists interested in its hardness, strength and flexi-bility. There is no doubt that today’s world economic development and social progress of nano-materials-based nanotechnology is bound to have an important impact. There-fore, the scientific research of nanomaterials has a very important significance. Among them, carbon nanomaterials is one of the most popular scientific research material.It is well known that the carbon element is one of the most important elements in nature, having different kinds of orbital hybridization characteristics, including sp, sp2and sp3. Therefore, carbon-based nanomaterials are diverse, including common graphite and diamond, and recently popular carbon nanotubes, carbon nanowires, fullerenes, and graphene. Recently, silicon monolayer similar to graphene, also known as silicene, has also been confirmed theoretically and experimentally, may become the latest pop-ular nanomaterials.In addition, in recent decades, based on the rapid development of computer sci-ence and technology with each passing day makes the theoretical basis of the first-principles calculations based on density functional theory and numerical calculation algorithm has also made a number of significant research progress and application prospects, especially in nano-materials science has made important research results, has attracted wide attention both at home and abroad. In this article, we mainly use the first-principles method to study and calculation of the electronic structure and its possible practical application of new carbon nanomaterials. In the first chapter, we briefly introduce the basic knowledge of the density func-tional theory, including the core issue of the Hartree-Fock equations, the Kohn-Sham equations and density functional theory:the exchange-correlation energy functional. Finally, we also introduced the common package based on density functional theory calculations.In the second chapter, we mainly use the structure and electromagnetic properties of first-principles calculations to study the diamond-based nanomaterials hosting the NV centers. Based on the electric double layer model, we found that the diamond surface decorations and sizes have effects on the relative stability of the NV0and NV-centers. Our considered three different diamond-based nanomaterials, including films, clusters and nanowires.In the third chapter, we mainly use the first-principles calculations to simulate the electronic structure of graphene on substrates. The interaction between graphene and its substrate has been studied, including silicon, diamond, strontium titanate (SrTiO3) and zinc oxide (ZnO).In the fourth chapter, we mainly use the first-principles calculations to design and study practical applications of silicene, including porous silicene as gas purification membrane and two-dimensional hybrid silicene-graphene nanocomposites for tunable p-n junctions.In the appendix, we introduced the linear scale program named ONPAS developed by our group. Our main job is to parallel the ONAPS and achieve high-performance parallel computing efficiency for large-scale electronic structure of nanomaterials. Our test results show that the parallel computing of ONPAS is far superior to SIESTA, including calculation time, memory and parallel efficiency.