拓扑超导体的基态和元激发性质

项目名称： 拓扑超导体的基态和元激发性质

项目编号： No.11204035

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 郝雷

作者单位： 东南大学

项目金额： 24万元

中文摘要： 拓扑绝缘体是时间反演不变的系统中存在的具有非平庸Z2拓扑序的相。2010年由掺杂拓扑绝缘体Bi2Se3得到了转变温度为3.8K的超导体CuxBi2Se3。人们猜想其中的配对可能是拓扑非平庸的。拓扑超导体中的马拉约那费米子元激发是实现拓扑量子计算的最有希望的载体。应用前景和基础研究上的重要性使得拓扑超导体的研究吸引了众多的关注。本项目中，我们将研究典型的二维和三维拓扑绝缘体的超导相的性质，包括其配对对称性和元激发性质等。一方面，我们将研究三维拓扑绝缘体Bi2X3（X为Se或Te）由一些特定的配对机制导致的配对的对称性及其非平庸的基态和元激发性质。另一方面，我们将研究具有自旋轨道耦合和电子强关联的二维六角蜂窝晶格中的对称破缺相，特别是该系统在强关联极限情况下的零掺杂和掺杂相图。对于相图中一些拓扑非平庸的超导相，我们将进一步研究其元激发和输运性质。

中文关键词： 拓扑绝缘体；拓扑超导体；元激发；拓扑序；强关联

英文摘要： Topological insulator is a phase discovered recently with nontrivial topological order characterized by a Z2 index. Its discovery brougt the study of topological phases to the forefront of condensed matter physics. In 2010, a new superconductor CuxBi2Se3 is prepared. CuxBi2Se3 is the first superconductor (T_C=3.8K) obtained by doping a topological insulator. Since then, it is guessed that this superconductor might have nontrivial topological order. Later, the superconducting phase of Bi2Te3 is also found under high pressure. One important property of topolgical superconductors is that they might support charge neutral topological excitations known as Majorana fermions. The Majorana fermion is widely considered as the most promising candidate to realize quantum computation. Because of this potential for application and also for its fundamental interest, topological superconductors have attracted a lot of attention. In this project, we will study the properties of the superconducting phase of typical two dimensional and three dimensional topological insulators, including their pairing symmetries and the elementary excitations therein. On one hand, we will study the pairing instability of the three dimensional topological insulators Bi2X3 (X is Se or Te). We will determine the pairing symmetries under various possi

英文关键词： Topological insulator；topological superconductor；elementary excitations；topological order；strong correlation