新型二维材料的pso结构预测及性能计算

摘要：最近有报道通过第一性原理计算预测出一种新的五边形二维结构，该结构由五个碳原子组成，并且是具有同石墨烯一样的高强度单层结构，因此被称为五边石墨烯。但与石墨烯不同的是该结构克服了石墨烯本身零带隙的缺陷，自带一个3.25eV的间接带隙，进而成为优秀的半导体材料。

本课题受到五边形石墨烯的启发，利用第四和第五主族元素对该结构中的碳元素进行替换，构造不同的五边形二维结构。并利用目前比较流行的结构预测算法CALYPSO对所有可能结构进行预测，最终得到其中最为稳定的SiP2结构。我们利用第一性原理对SiP2五边形二维结构的能带结构和光电性质等进行了系统而全面的计算。发现SiP2五边形为间接带隙半导体结构。并且该带隙在单、双轴的不同应力场条件下带隙大小可控，性质不变，通过其声子谱分析该二维结构仍然可以稳定存在，因此该结构在光电子领域有较大地应用前景。本工作为新型二维半导体材料的结构预测和实验合成提供了坚实的理论基础和实验依据。

关键词五边形二维结构 CALYPSO 能带结构光电性质第一性原理

毕业设计说明书外文摘要

Title Prediction of the new structure and properties of two-dimensional materials by CALYPSO calculation

Abstract：Recently, a 2D metastable carbon allotrope, penta-graphene, composed entirely of carbon pentagons and resembling the Cairo pentagonal tiling, is proposed by the first principles calculations. The structure consists of five carbon elements, and is of high strength single layer structure like graphene, so it is called penta-graphene. However, unlike graphene, this structure overcomes the defect of zero band gap of graphene itself, with an indirect band gap of 3.25eV, which makes it an excellent semiconductor material.

This thesis is inspired by the penta-graphene, using IV and V family elements to replace the carbon elements in the structure, and construct different pentagonal two-dimensional structure. A new structure prediction method called Calypso is used to predict the all the possible structure, and the most stable SiP2 structure is obtained. We calculated the band structure and photoelectric properties of the SiP2 pentagonal two-dimensional structure by the first principles systematically and comprehensively. We found that the SiP2 pentagon has an indirect bandgap of 2.4 eV. And the band gap is tunable in the uniaxial or biaxial strain field. And the two-dimensional structure can still remain stable seen from the phonon spectrum, so this structure has a better application prospect in the field of optoelectronics. This work provides a solid theoretical basis and experimental basis for structural prediction and experimental synthesis of new two-dimensional semiconductor materials.

Keywords Pentagonal two-dimensional structure CALYPSO Band structure Photoelectric properties First principle

1 绪论 1

1.1五边形石墨烯简介 1

1.2五边形硅二碳化物（PSiC2）简介 3

1.3第一性原理计算 5

1.4论文主要内容 7

2 计算软件及其理论基础 8

2.1 新型二维材料的pso结构预测及性能计算:http://www.chuibin.com/cailiao/lunwen_205123.html