CAREER: Manipulating Topology and Correlations in 2D Heterostructures by Dynamic Structural Control

非技术摘要：电流在材料中的流动方式取决于其原子的排列方式。通常情况下，原子的排列是固定在一种不易改变的晶体模式中。该项目研究如何动态改变材料中的晶体模式，以控制电流和了解其量子特性为目标。所研究的特定材料只有几个原子厚，即所谓的二维或“二维”材料。二维材料可以像纸张一样堆叠，单个的纸张可以很容易地滑动和旋转，从而改变内部的晶体图案。研究小组正在开发技术，以快速修改二维材料堆栈中的晶体模式，以便研究对电流的影响。这些研究将在接近绝对零度的低温冰箱中进行，在那里携带电的电子的量子行为更加明显。该项目的成功将推进量子电学性质的知识，这是开发计算机和无线通信新电子技术的关键。该研究项目将与一项教育任务携手并进，重点是指导学生，增加来自未被充分代表的少数民族学生的参与，以及通过科学演示和基于物理的视频游戏进行公众宣传。技术摘要：二维（2d）材料的异质结构表现出广泛的电子现象，这些现象敏感地依赖于内部扭曲界面的物理结构。研究小组开发了一种技术，可以动态地修改二维材料器件的物理结构，这种技术是通过二维层之间的低摩擦滑动来实现的。本项目拟将这些动态结构控制技术应用于：(1)研究由滑动莫尔莫尔超晶格引起的动态电子效应；(2)通过扭角和层位移的原位控制，系统地研究多莫尔莫尔系统的相关物理和拓扑物理。这项研究的成功结果将导致用于操纵绝缘体中的电子的拓扑电荷泵的发展，以及对莫伊莫尔变如何改变电子行为的更深入理解。该研究项目将为将学生培养为独立科学家的教育活动奠定基础。首席研究员将实施一个规范的博士课程，为学生提供多样化的职业机会，重点是技术技能，如纳米制造和编程，以及软技能，如管理和沟通。这个培训项目将成为增加STEM中代表性不足的学生参与的场所。此外，这项活动包括多种方法来增加公众对科学的参与，包括高中科学暑期项目，向小学生分发量子材料演示，以及开发基于物理的视频游戏。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical Abstract:The way electricity flows in a material depends on how its atoms are arranged. Normally, the arrangement of atoms is frozen in a crystal pattern that cannot be easily changed. This project studies how to dynamically change the crystal pattern in a material, with the goals of controlling the flow of electricity and understanding its quantum properties. The specific materials studied are only a few atoms thick, so-called two-dimensional or “2D” materials. 2D materials can be stacked like sheets of paper and the individual sheets can easily slide and rotate, which changes the internal crystal pattern. The research team is developing techniques to rapidly modify the crystal pattern in a 2D material stack so that the effects on electricity flow can be studied. These studies will be performed in a cryogenic refrigerator at temperatures near absolute zero where the quantum behavior of the electrons carrying the electricity is more apparent. The success of this project will advance knowledge of quantum electrical properties which is key to developing new electronic technologies for computers and wireless communication. This research project will go hand-in-hand with an educational mission focused on mentoring students, increasing participation of students from underrepresented minorities, and public outreach by science demos and physics-based video games.Technical Abstract:Heterostructures of 2-dimensional (2d) materials exhibit a wide range of electronic phenomena that depend sensitively on the physical structure of internal twisted interfaces. The research team has developed techniques to dynamically modify the physical structure of 2d material devices in-situ that are enabled by the low friction sliding between 2d layers. This project proposes to apply these dynamic structural control techniques to (1) investigate dynamic electronic effects that arise from sliding moiré superlattices, and (2) systematically study correlated and topological physics of multi-moiré systems by in-situ control of twist angle and layer displacement. The successful outcome of this research would lead to the development of topological charge pumps for manipulating electrons in insulators, as well as a deeper understanding of how moirés can modify electronic behaviors. The research project will provide a foundation for educational activities focused on training students as independent scientists. The principal investigator will implement a codified Ph.D. curriculum that prepares students for diverse career opportunities, with an emphasis on both technical skills, such as nanofabrication and programming, as well as soft skills, such as management and communication. This training program will serve as a venue for increasing the participation of students who are underrepresented in STEM. Furthermore, this activity includes multiple approaches to increasing public engagement in the sciences, including a high school science summer program, the distribution of quantum materials demos to elementary school students, and the development of physics-based video games.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.