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资助旨在进行新的和完美的拓扑绝缘体/超导体的晶体生长，并探索完美生长的拓扑绝缘体(TIS)的狄拉克表面状态。它还旨在将实验凝聚态物理学的研究与密苏里科技大学(S&T)独特的物理教育项目的发展结合起来。新的方法将被用来生长完美的体绝缘钛酸钛和制备大表面积比的钛纳米线阵列。这些完美的拓扑材料是狄拉克表面电流检测所必需的，这对新的物理探索，如Majorana费米子和轴子电动力学的研究，以及诸如自旋电子学和量子计算设备的技术应用都是重要的。用Shubnikov-de Haas振荡、Aharonov-Bohm效应和Altshuler-Aronov-Spivak干涉对理想生长的TiS进行测量，以估算表面Dirac电子的有效质量和衰变长度。然后将在高达45T的磁场下进行表面电阻率测量，以研究分数量子霍尔效应，这是该领域关于物质拓扑态中相互作用和强关联的作用的重大探索。*非技术摘要*拓扑绝缘体(TI)是一种新型的量子材料，其体相具有绝缘性，但其表面具有较高的电子导电性。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，由于现有TIS的不完善，表面传输测量是具有挑战性的。一种新的合成技术，利用缩小的限制反应空间，将被应用于生长完美的块体绝缘晶体，以允许表面电流检测。这种对表面电子或表面Dirac态的电子输运检测对于无散热自旋电子器件是必要的，在这种器件中，电子自旋操纵可以通过连接完美的TI和超导体来执行，以实现潜在的容错量子计算应用。此外，TIS可以作为一座桥梁，将高能和凝聚态物理学家聚集在一起，寻找人们长期寻找的粒子，如Majorana费米子，即费米子，它本身就是反粒子，是电场和磁场相互作用的中间粒子，称为轴子，这可能为揭示宇宙学中暗物质的奥秘提供线索。这笔职业助学金还有助于整合S&T教授的固体物理课程中的材料合成，并针对当地K-12学生举办物理节目。

****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.