Beyond Conventional Methods: Chemical Routes to Dope Topological Insulator Nanostructures and Two-Dimensional Materials Magnetically

** 非技术描述 ** 该奖项来自材料研究部的凝聚态物理计划，支持耶鲁大学的一个项目，为拓扑绝缘体纳米结构开发新的化学掺杂方法，以缓解该领域面临的当前材料挑战。拓扑绝缘体具有奇异的导电表面状态，可以用作不产生废热的信息载体。 因此拓扑绝缘体可以取代现有的铜互连线，从而为社会带来巨大的能源消耗。这项研究将使拓扑绝缘体作为替代互连的实现更接近现实。此外，这些方法可以成功地应用于二维分层半导体，以创建稀磁半导体，为社会带来更广泛的影响。稀磁半导体在自旋电子学应用中得到了广泛的研究。这项工作有助于培训熟练的技术人员队伍，并包含有关纳米材料的新课程开发的内容。此外，该项目还促进代表性不足群体的参与。技术描述 ** 该奖项由耶鲁大学材料研究部凝聚态物理计划颁发，支持一个项目，该项目旨在开发新的化学方法，用磁性杂质掺杂拓扑绝缘体纳米材料，并在拓扑表面态中打开带隙。研究了两种化学方法。第一种方法是在层状拓扑绝缘体的货车范德华能隙处嵌入磁性原子、离子和分子。第二种方法采用分子自旋的拓扑绝缘体纳米结构的表面改性。这些方法表现出优于常规掺杂方法的显著优点：1）更高浓度的磁性掺杂剂，2）没有磁性掺杂剂的聚集，3）磁性掺杂剂空间有序地形成反铁磁性或铁磁性，以及4）对其他二维层状材料的广泛适用性。将制造纳米器件来测量低温下的磁输运以表征掺杂。这项研究的成功结果将导致一个材料平台，在这个平台上，可以探索基本的凝聚态物理现象，以提高拓扑表面态的带隙，拓扑磁电效应和量子反常霍尔效应的知识。预计该项目中开发的方法可以是通用的。该研究涉及培训本科生独立进行研究，开发纳米技术课程的新组件，并通过出版物和会议演示和推广传播知识。

**Non-Technical Description**This award from the Condensed Matter Physics Program of the Division of Materials Research supports Yale University with a project to develop novel chemical doping methods for topological insulator nanostructures to alleviate current materials challenges facing the field. Topological insulators possess exotic conducting surface states that can be used as information carriers that do not generate wasted heat. Thus topological insulators can replace current copper interconnects, resulting in great reduction of energy consumption for the society. This research will bring the realization of topological insulators as alternative interconnects one step closer to reality. Additionally, the methods can be successfully applied to two-dimensional, layered semiconductors to create dilute magnetic semiconductors for much broader impact for the society. Dilute magnetic semiconductors are widely studied for spintronics applications. The work contributes to the training of skilled technical workforce and contains elements for new course development on nanomaterials. In addition, the project promotes the participation of underrepresented groups.**Technical Description**This award from the Condensed Matter Physics Program of the Division of Materials Research to Yale University supports a project to develop novel chemical methods to dope topological insulator nanomaterials with magnetic impurities, and to open a band gap in the topological surface states. Two chemical methods are investigated. The first method employs intercalation of magnetic atoms, ions, and molecules at the Van der Waals gap of layered topological insulators. The second method employs surface modification of topological insulator nanostructures with molecular spins. These methods exhibit significant advantages over conventional doping methods: 1) higher concentration of magnetic dopants, 2) no clustering of magnetic dopants, 3) spatial ordering of magnetic dopants into anti-ferromagnetism or ferromagnetism, and 4) broad applicability to other two-dimensional layered materials. Nanodevices will be fabricated to measure magnetotransport at low temperature to characterize the doping. The successful outcome of this research will lead to a materials platform in which fundamental condensed matter physics phenomena can be explored to advance knowledge in band gap in topological surface states, in topological magneto-electric effect, and quantum anomalous Hall effect. It is anticipated that the methodology developed in this project can be general. The research involves training undergraduate students to conduct research independently, developing new components for a nanotechnology course, and dissemination of knowledge through publications and conference presentations and outreach..