Imaging of Electronic Correlations and Symmetry Breaking Effects in Twisted Van der Waals Materials

非技术：该项目旨在探索一次组装一个原子层的工程材料的电子性质，从石墨烯和某些半导体，即所谓的过渡金属二卤化物开始。对于精确定义的层与层之间的旋转失准角，这些材料中的电子相互作用强烈，从而导致相关量子电子相的出现。研究小组将使用扫描隧道显微镜和光谱技术在不同的几何结构中对这些新出现的相进行成像。这种方法将使团队能够深入了解相关阶段的微观属性如何与它们的整体传输特征相关联。这些信息可以用来开发新型的电子量子器件。该团队将通过国际会议、期刊文章、特邀演讲、公开发布的博客文章和面向广大受众的教育视频来传播项目成果。除了研究部分，该项目旨在通过暑期实习和针对代表不足的少数族裔的方案以及针对帕萨迪纳学区高中生和教师的外联活动，为整合本科教育和增加多样性提供充足的机会。技术：层状准二维晶体的发现为设计可调谐电子系统提供了一种新方法，在该系统中，电子-电子相互作用通过堆积层的旋转排列(扭曲)来控制。本项目的重点是探索扭曲多层石墨烯和过渡金属二卤化物异质结构中新出现的相关量子电子相的性质，包括超导和轨道铁磁性。主要目标之一是利用扫描隧道显微镜和光谱学，并通过研究栅极可调多端几何结构中的异质结构，建立对这些新兴相中潜在的对称性和对称性破缺现象的基本理解。这项研究项目伴随着一项广泛的指导和推广计划，旨在为研究生和本科生在科学和工业领域的成功职业生涯做好准备，并帮助教育公众有关量子科学和纳米技术的知识。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non Technical:This project aims to explore the electronic properties of engineered materials that are assembled one atomic layer at a time, starting from individual sheets of graphene and certain semiconductors, so-called transition metal dichalcogenides. For precise well-defined rotational misalignment angle between the layers, electrons in these materials strongly interact which leads to the emergence of correlated quantum electronic phases. The research team will image these emerging phases using scanning tunneling microscopy and spectroscopy techniques in various geometries. This approach will allow the team to gain insights into how the microscopic properties of correlated phases relate to their overall transport signatures. This information can be used to develop novel electronic quantum devices. The team will disseminate the project results through international conferences, journal articles, invited talks, publicly available blog posts, and educational videos targeting a broad audience. Besides the research component, this project aims to provide ample opportunities for integrating undergraduate education and increasing diversity through summer internships and programs for underrepresented minorities and outreach activities targeting high-school students and teachers from the Pasadena School District. Technical:The discovery of layered quasi-two-dimensional crystals enabled a new way of designing tunable electronic systems in which electron-electron interactions are controlled through the rotational alignment (twist) of the stacked layers. The focus of this project is to explore properties of emerging correlated quantum electronic phases, including superconductivity and orbital ferromagnetism, in twisted multi-layer graphene and transition metal dichalcogenides heterostructures. One of the main goals is to establish a basic understanding of underlying symmetries and symmetry breaking phenomena that occur in these emerging phases using scanning tunneling microscopy and spectroscopy and by studying heterostructures in gate-tunable multi-terminal geometries. This research project is accompanied by an extensive mentoring and outreach plan aimed to prepare graduate and undergraduate students for successful careers in science and industry and help educate the public about quantum science and nanotechnology.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.