毕业论文移动版

摘要通过文献调研以及有关超导书籍学习，笔者对超导基本知识进行了整理，包括超导的基本性质，超导发展的历史以及超导研究的现状等。某些材料在低温下进入完全不一样的状态，其显著特征是零电阻性和完全抗磁性，这种特殊状态称为超导态。早期发现的超导体其机制可以用BCS理论解释。这种理论认为超导的形成首先是电子通过电子声子作用而相互吸引形成库珀对，然后库珀对在动量空间发生凝聚，从而形成超导。根据库珀对的对称性不同，超导体可分成s波超导体，p波超导体，d波超导体等。传统BCS超导体多为s波超导体，而包括铜基超导体、铁基高温超导材料在内的超导体可能是d波和具有结点的s波超导。近年来理论和实验发现p波超导体可能具有非平凡的拓扑学性质，这种表面是金属内部是超导体的材料被称为拓扑超导体。目前拓扑超导体的实现方式是将拓扑绝缘体进行性质的扭转，可能实现的方式有半导体参杂和压力诱导等方式。本文最后对最新发现的准一维超导材料K2Cr3As3的超导配对对称性作了介绍，并提出一种实验检验方案。48199

Abstract Through literature research and Study on superconducting books, the author summarized the basic knowledge of superconductivity, including basic properties of superconductivity, the history of the development of superconductivity. Some of the material into the state of matter which is completely different in low temperature condition,  it’s significant characteristics are that the zero resistance and completely diamagnetism. This special state of matter called the superconducting state. The mechanism of early can be explained by BCS theory. This theory holds that the first is the formation of superconducting electrons through a mutual attraction of Cooper pair, the pairing of electrons in the momentum space agglomeration, thus forming a superconducting.According to the symmetry of the Cooper pair, superconductors can be pided into S-wave superconductor,  P-wave superconductor, D-wave superconductor. The traditional BCS superconductors are S-wave superconductor, but including copper, iron based superconductors superconducting materials,  may be the D-wave and S-wave superconductor with borrow. In recent years, the theory and experiment found that P-wave superconductor may have non trivial topological property, this superconductor inside and metal outside material is called topological superconductor. The current implementation of superconductors topology is reversing a topological insulator’s properties and the possible ways are doping and pressure induced etc.

毕业论文关键词： 超导； 库珀对； 对称性； 拓扑超导

Keyword: superconductivity； Cooper pair；Symmetry ；topological superconductors

目    录

一、 超导的起源和发展 6

二、 超导基本理论 10

1． 超导电性一般性质 10

2． BCS理论 15

3． 超导配对对称性 17

三、 拓扑绝缘体 19

1. 能带绝缘体 19

2. 量子霍尔效应家族 20

3. 拓扑绝缘体 24

四、 拓扑超导体 27

1. 拓扑绝缘体和s波超导体的临界效应 27

2. 拓扑超导体 27

3. 可能的实现方式及材料 28

五、 新型准一维超导材料K2Cr3As3 (责任编辑：qin)