拓扑绝缘体.本科毕业汇报资料

2016 届毕业论文

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目：新型拓扑绝缘材料的研究

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摘 要

拓扑绝缘体是一种新的量子物态，为近几年来凝聚态物理学的重要科学前沿之一，已经引起的巨大的研究热潮。拓扑绝缘体具有新奇的性质，虽然与普通绝缘体一样具有能隙，但拓扑性质不同，在自旋一轨道耦合作用下，在其表面或与普通绝缘体的界面上会出现无能隙、自旋劈裂且具有线性色散关系的表面/界面态。这些态受时间反演对称性保护，不会受到杂质和无序的影响，由无质量的狄拉克(Dirac)方程所描述。从广义上来说，拓扑绝缘体可以分为两大类 ：一类是破坏时间反演的量子霍尔体系，另一类是新近发现的时间反演不变的拓扑绝缘体，这些材料的奇特物理性质存在着很好的应用前景。理论上预言，拓扑绝缘体和磁性材料或超导材料的界面，还可能发现新的物质相和预言的Majorana费米子，它们在未来的自旋电子学和量子计算中将会有重要应用。拓扑绝缘体还与近年的研究热点如量子霍尔效应、量子自旋霍尔效应等领域紧密相连，其基本特征都是利用物质中电子能带的拓扑性质来实现各种新奇的物理性质。

关键词：拓扑绝缘体，量子霍尔效应，量子自旋霍尔效应，Majorana费米子

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Abstract

In recent years, one of the important frontiers in condensed matter physics, topological insulators are a new quantum state, which has attract many researchers attention. Topological insulators show some novel properties, although normal insulator has the same energy gap, but topological properties are different. Under the action of spin-orbit coupling interaction, on the surface or or with normal insulator interface will appear gapless, spin-splitting and with the linear dispersion relation of surface or interface states. These states are conserved by the time reversal symmetry and are not affected by the effect of the impurities and disorder, which is described by the massless Dirac equation. Broadly defined, topological insulators can be separated into two categories: a class is destroy time reversal of the quantum Hall system, another kind is the newly discovered time reversal invariant topological insulators, peculiar physical properties of these materials exist very good application prospect. Theoretically predicted, the interface of topological insulators and magnetic or superconducting material, may also find new material phase and the prophecy of Majorana fermion, they will have important applications in the future spintronics and quantum computing . Topological insulators also are closely linked with the research hotspot in recent years, such as the quantum Hall effect, quantum spin Hall effect and other fields. Its basic characteristics are to achieve a variety of novel physical properties by using the topological property of the material of the electronic band.

Keywords:Topological

insulator;quantum hall effect;quantum

spin-Hall effect;Majorana fermion

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