低维碳纳米体系的电子结构及自旋输运-物理学专业论文.docxVIP

II II Abstract Low-dimensional carbon nanomaterials have always been the focus of scientific research. In 2004, the discovery of graphene has promoted the study of low-dimensional carbon nanomaterials into a new round of upsurge. Especially in the field of electronics, graphene has a lot of unique electronic transport properties and spin transport properties, which has injected new vitality into the research of new generation of the nanoselectronics and spin nanoelectronics. After the discovery of graphene, in 2010 another two-dimensional planar structure of lower dimensional carbon nanomaterial, graphyne was found by the scientists of China. In this kind of nanostructure, there are two hybrid modes (sp and sp2). Graphyne not only has the similar properties to graphene, but also has excellent semiconducting properties, which graphene does not own. It creates that graphyne would have broad application prospects in the new generation of optoelectronic device and vacuum nanodevices. Using Green function method, we have studied the spin transport properties of armchair graphene nanoribbons and the electronic structures of graphyne-based systems in this thesis. The major results summarized as follows: Using Green’s function method, we have investigated the spin transport properties of armchair graphene nanoribbons (AGNRs) under magnetic field and uniaxial strain. Our results show that it is very difficult to transform narrow AGNRs directly from semiconductors to spin gapless semiconductors (SGS) by applying magnetic fields. However, as a uniaxial strain is exerted on the nanoribbons, the AGNRs can transform to SGS by a small magnetic field. The combination mode between magnetic field and uniaxial strain displays a nonmonotonic arch-pattern relationship. In addition, we found that the combination mode is associated with the widths of nanoribbons, which exhibits group behaviours. We have investigated the electronic structures of graphyne nanostructures. All the graphyne-ba