CAREER: Surface State Studies of Topological Insulators/Superconductors

****技术摘要****这项由材料研究部支持的职业生涯资助旨在进行新型完美拓扑绝缘体/超导体的晶体生长和完美生长拓扑绝缘体（TIs）的狄拉克表面态的探索。它还旨在将实验凝聚态物理的研究与密苏里科技大学（S&amp；T）独特的物理教育计划的发展结合起来。新的方法将用于生长完美的块状绝缘TI和制造大表面体积比的TI纳米线阵列。这些完美的拓扑材料是狄拉克表面电流检测所必需的，这对于新的物理探索，如马约拉纳费米子和轴子电动力学的研究，以及自旋电子和量子计算设备等技术应用都是重要的。在完全生长的ti上进行了Shubnikov-de Haas振荡、Aharonov-Bohm效应和Altshuler-Aronov-Spivak干涉，以估计表面狄拉克电子的有效质量和衰变长度。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，这是一个关于物质拓扑状态中相互作用和强相关性的领域的重大探索。****非技术摘要****拓扑绝缘体（Topological insulator， TI）是一种既具有绝缘性又具有表面高导电性的新型量子材料。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，由于现有ti的不完善，地面运输测量具有挑战性。一种新的合成技术，利用减少限制的反应空间，将被用于生长完美的体绝缘晶体，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无散热的自旋电子器件是必要的，其中电子自旋操纵可以通过连接完美的TI和超导体来执行，用于潜在的容错量子计算应用。此外，它可以作为一个桥梁，将高能和凝聚态物理学家聚集在一起，寻找长期寻找的粒子，如马约拉纳费米子，即一种费米子，它本身就是反粒子，也是一种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整合到S&amp；T教授的固态物理课程中，并为当地K-12学生提供物理表演。

****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.