CAREER: Surface State Studies of Topological Insulators/Superconductors

* 技术摘要 * 该职业资助由材料研究部支持，旨在进行新的完美拓扑绝缘体/超导体的晶体生长，并探索完美生长的拓扑绝缘体（TI）的狄拉克表面态。它还旨在整合实验凝聚态物理学的研究和密苏里州科技大学（ST）独特的物理教育计划的发展。新的方法将用于生长完美的体绝缘TI和制备大的表面体积比的TI纳米线阵列。这些完美的拓扑材料是必要的狄拉克表面电流检测，这是重要的新的物理探索，如马约拉纳费米子和轴子电动力学的研究，以及技术应用，如自旋电子学和量子计算设备。利用Shubnikov-de哈斯振荡、Aharonov-Bohm效应和Altshuler-Aronov-Spivak干涉等方法，对完全生长的TI进行了表面狄拉克电子有效质量和衰变长度的估算。然后将在高达45 T的磁场下进行表面电阻率测量，以研究分数量子霍尔效应，这是该领域关于相互作用和强相关性在物质拓扑状态中的作用的一个大探索。* 非技术摘要 * 拓扑绝缘体（Topological insulator，TI）是一种新型的量子材料，其本体具有绝缘性，但表面具有高的电子导电性。这种表面导电状态被预测为未来计算技术的解决方案。然而，表面输运测量是具有挑战性的，由于目前现有的TI的缺陷。一种新的合成技术，利用减少限制反应空间将被应用于生长完美的大块绝缘晶体，以允许表面电流检测。这种表面电子或表面狄拉克态的电子输运检测对于热耗散较少的自旋电子器件是必要的，其中电子自旋操纵可以通过将完美的TI和超导体连接在一起来执行，以用于潜在的容错量子计算应用。此外，TI可以作为一个桥梁，将高能物理学家和凝聚态物理学家聚集在一起，寻找长期寻找的粒子，例如Majorana费米子，即费米子，它是自己的反粒子，也是电场和磁场相互作用的中间粒子，称为轴子，它可以为宇宙学中的暗物质之谜提供线索。这项职业补助金还有助于将材料合成纳入S T教授的固态物理课程，并为当地K-12学生提供物理节目。

****Technical Abstract****This CAREER grant supported by the Division Materials Research aims to have a crystal growth of new and perfect topological insulators/superconductors and exploration of Dirac surface state of the perfectly grown topological insulators (TIs). It also aims to integrate research in experimental condensed matter physics and development of a unique physics educational program at Missouri University of Science and Technology (S&T). New methods will be used to grow perfect bulk insulating TIs and to fabricate large surface-to-volume ratio of TI nanowire arrays. These perfect topological materials are necessary for Dirac surface current detection which is important for both new physics exploration such as studies of Majorana fermion and axion electrodynamics, and technological applications such as spintronic and quantum computing devices. Shubnikov-de Haas oscillations, Aharonov-Bohm effect and Altshuler-Aronov-Spivak interference on the perfectly grown TIs will be performed to estimate surface Dirac electron effective mass and decay length. Surface resistivity measurements under magnetic fields up to 45 T will then be carried out for the investigation of fractional quantum Hall effect which is a big quest in the field concerning the role of interactions and strong correlations in topological states of matter. ****Non-Technical Abstract****Topological insulator (TI) is a new quantum material which has insulating property in its bulk but has high conductivity of electrons on its surface. This surface conducting state is predicted to be a solution for future computing technology. However, surface transport measurements are challenging due to the imperfections of the current existing TIs. A new synthesis technique that utilizes a reduced confining reaction space will be applied to grow perfect bulk insulating crystals in order to permit surface current detection. This electronic transport detection of the surface electrons or the surface Dirac state is necessary for heat dissipation-less spintronic devices where electron spin manipulation can be performed by interfacing a perfect TI and a superconductor for potential fault-tolerant quantum computing applications. Besides, TIs can act as a bridge to bring together high energy and condensed matter physicists to search for long-sought particle such as the Majorana fermion i.e. a fermion which is its own anti-particle and an intermediate particle for electric and magnetic field interactions called the axion which could provide a clue to the mystery of dark matter in cosmology. This CAREER grant also helps to integrate the material synthesis in solid state physics course taught in S&T and to present physics shows targeted to local K-12 students.