Emergent Physics in Correlated, Spin-orbit Coupled Materials

* 技术摘要 * 本项目主要关注相关性相关的自旋轨道耦合系统。虽然最近有许多理论研究描述了这种材料中的新相，但没有一个有趣的预测，如外尔半金属态或轴子绝缘体，尚未被实验观察到。低温扫描隧道显微镜（STM）是探测复杂材料电子结构的最佳方法之一，这些材料通常表现出纳米级的不均匀性。STM将被用来研究相关的自旋轨道材料，如烧绿石和Ruddlesden-Popper系列的铱酸盐，或Heusler化合物。对这些系统基本性质的理解的进展可能会导致自旋轨道耦合复杂系统的新范式。通过理论合作者的密切反馈以及在获得单晶和薄膜样品方面的快速转变，该小组将能够迅速探索各种材料以寻找新的相。综合教育活动包括一个新的结构化部门范围内的博士后指导计划，并参与研究的本科生，这将有助于培养下一代科学家，以及通过教育学院正在进行的推广计划，这将对初中和高中受过培训的科学教师的数量产生可衡量的影响。在探索固体中的电子和原子的物理学中，一个新的和令人兴奋的前沿是探索存在一个以上主导相互作用的材料。自旋轨道耦合是电子的量子力学自旋与其轨道性质之间的相互作用。当自旋-轨道相互作用很强时，材料就会显示出新的效应。然而，在这些系统中加入电子-电子相互作用可以大大扩展新特性的范围。虽然最近有许多关于这种材料中可能的新状态的理论研究，但到目前为止很少进行实验研究。此外，还没有一个有趣的预测阶段被实验观察到。该项目侧重于材料的基本物理学，其中具有多种相互作用，可以相互竞争或相互帮助。为了研究这些材料，我们将使用扫描隧道显微镜的工具，它不仅能够对单个原子进行成像，还能够移动单个原子来构建人工原子尺度的结构。任何新状态的发现和对它们性质的理解，对于推进我们在这一新领域的知识都至关重要。该项目将支持研究生和博士后谁将学习实验技术和材料物理学在当前研究的前沿。

****Technical Abstract****This project focuses on spin-orbit coupled systems where correlations are relevant. While there have been many recent theoretical studies describing novel phases in such materials, none of the intriguing predictions such as the Weyl semi-metal state or axion insulators has as yet been experimentally observed. Low temperature scanning tunneling microscopy (STM) is one of the best methods to probe the electronic structure of complex materials, which often exhibit nanoscale inhomogeneities. STM will be used to study correlated spin-orbit materials such as the pyrochlore and Ruddlesden-Popper series of iridates, or the Heusler compounds. Progress in understanding fundamental properties of these systems may lead to new paradigms in spin-orbit coupled complex systems. With close feedback from theory collaborators and quick turn around in obtaining single crystal and thin film samples, the group will rapidly be able to explore a variety of materials in search of novel phases. The integrated education activities include a new structured department-wide mentoring plan for post-docs, and involvement of undergraduates in research, which will help train the next generation of scientists, as well as an ongoing outreach program through the School of Education, which will have a measurable impact on the numbers of trained science teachers in middle- and high schools.****Non-Technical Abstract****A new and exciting frontier in the exploring the physics of electrons and atoms in solids is the exploration of materials where there is more than one dominating interaction. Spin-orbit coupling is an interaction between the quantum mechanical spin of an electron and its orbital properties. When spin-orbit interaction is strong, materials are known to show novel effects. However, adding electron-electron interactions to these systems can vastly expand the range of novel properties. While there have been many recent theoretical studies on the possible new states in such materials, very few experimental studies have been carried out so far. Moreover, none of the intriguing predicted phases has as yet been experimentally observed. This project focuses on the fundamental physics of materials where with multiple interactions, which can either compete or aid one another. To study these materials we will use the tool of scanning tunneling microscopy, which has the power to not only image single atoms but also to move individual atoms to build artificial atomic scale structures. Any discoveries of novel states and understanding their properties will be vital to advancing our knowledge in this new field. This project will support graduate students and post-docs who will learn experimental techniques and the physics of materials at the cutting edge of current research.