Collaborative Research: Twist Control of Correlated Physics in Two Dimensions

非技术描述材料科学中的创新推动了从根本上改变社会运行方式的技术的创造。多年来，人们一直对基于量子力学原理的计算机的可能性感到兴奋。这一梦想仍然没有实现，这既是因为材料中缺乏可调的量子行为，也是因为培训一支精通量子的劳动力的管道。该项目的主要研究目标是通过实现对量子材料物理的前所未有的控制来加速下一代技术的生产。该项目将专门研究原子薄材料，这些材料各自具有强烈的电子相互作用，以了解这些相互作用如何通过层工程来操纵。这种通过扭转层来设计量子态的新能力可以加速内存和计算技术的创造，这些技术在性能和能效方面都优于现状。量子材料中的扭角物理也为电子之间的相互作用如何导致意外行为提供了新的见解。该项目的教育目标是通过向高中生和本科生传授量子技术的可能职业道路以及如何遵循这些路径来建立一支懂量子的劳动力队伍。量子劳动力发展通过跨机构、学术界和行业的活动进行，这些活动包括：1)学生可以直接与行业专家互动的“量子职业”活动，2)主要研究机构的外展活动，以及3)中学科学夏令营。这些活动将对学生在日益增长的量子高科技行业中为激动人心的职业生涯做好准备产生长期的影响。技术说明本项目的目标是通过探索二硫化钽的扭曲异质结构，发现层状量子材料中层间相互作用的作用。现有的层状量子材料研究证明了电子基态和层排列之间的联系，但这些研究仅限于一小部分自然发生的堆积配置，并且充满了矛盾。通过利用扭曲可调的异质结构和一系列跨越纳米级到介观级物理的表征和建模，该项目系统地探索了二硫化钽中的强关联物理，以揭示详细说明Mott物理、电荷密度波、磁性和金属状态相互作用的总相空间。这项研究是通过新汉普郡大学和乔治梅森大学以及布鲁克海文国家实验室量子材料出版社的合作实现的。主要的研究活动包括：1)创造第一个由强相关材料组成的扭曲异质结构；2)通过纳米扫描隧道显微镜和介观磁拉曼光谱的关联，阐明二硫化钽的扭曲角结构-性质关系；以及3)发现非周期性对一类新的扭曲量子准晶的影响。来自这些努力的实验结果可以为海军研究实验室的合作者创建扭曲物理的理论模型提供信息，从而导致对层状固体中量子出现的更广泛的理解。这项工作中建立的结构-性质关系为扭曲异质结构(如可切换基态)中的设计者量子行为提供了一套指导原则，通过明智地选择2D材料和层取向。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。

Nontechnical DescriptionInnovations in materials science drive the creation of technologies that fundamentally alter how societies function. For years there has been excitement around the possibility of computers based on the principles of quantum mechanics. This dream remains unrealized both due to the lack of tunable quantum behaviors in materials and a pipeline for training a quantum-literate workforce. The main research objective of this project is to accelerate the production of next-generation technologies by achieving unprecedented control over the physics in quantum materials. The project will specifically investigate atomically thin materials that individually have strong electronic interactions to understand how these interactions may be manipulated through layer engineering. This new ability to design quantum states by twisting layers can hasten the creation of memory and computing technologies that are superior in performance and energy efficiency to the status quo. Twist angle physics in quantum materials also provides new insight into how interactions between electrons can lead to unexpected behaviors. The education goal of this project is to build a quantum-literate workforce by teaching high school and undergraduate students about possible career paths in quantum technology as well as how to follow these paths. Quantum workforce development is carried out through cross-institution, academia-industry events that include: 1) a ‘Careers in Quantum’ event where students can directly interact with industry experts, 2) outreach events at the Principal Investigators’ institutions, and 3) a middle school science camp. These activities are poised to make a long-standing impact in the preparation of students for exciting careers in an increasingly quantum high-tech industry.Technical DescriptionThe objective of this project is to discover the role of interlayer interactions in layered quantum materials through the exploration of twisted heterostructures of tantalum disulfide. Existing studies of layered quantum materials demonstrate connections between electronic ground state and layer alignment, but these are limited to a small set of naturally occurring stacking configurations and wrought with contradictions. By leveraging twist-tunable heterostructures and a range of characterization and modeling that spans nanoscale to mesoscale physics, this project systematically explores strongly correlated physics in tantalum disulfide to uncover the total phase space detailing the interplay of Mott physics, charge density waves, magnetism, and metallic states. This research is enabled through a partnership between the University of New Hampshire and George Mason University and with the Quantum Material Press at Brookhaven National Laboratory. The central research activities are: 1) creating the first twisted heterostructures comprised of strongly correlated materials; 2) elucidating the twist-angle structure-property relationships in tantalum disulfide through the correlation of nanoscale scanning tunneling microscopy and mesoscale magneto-Raman spectroscopy; and 3) discovering the impact of aperiodicity in a new class of twisted quantum quasicrystals. Experimental results from these efforts can inform the creation of theoretical models of twist physics by collaborators at the Naval Research Laboratory, leading to a more general understanding of quantum emergence in layered solids. The structure-property relationships established in this work provide a set of guiding principles for designer quantum behaviors in twisted heterostructures, such as switchable ground states, through the judicious choice of 2D material and layer orientation.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.