CAREER: Bicrystallography-informed Mechanics of Two-dimensional Heterointerfaces

该学院早期职业发展（Career）奖将支持研究如何利用应变来研究异质界面的结构响应，以设计和合成原子薄二维材料系统。通过堆叠不同的二维材料形成的异质结构表现出优异的机械和电子性能，如超润滑性、高应变容限和相关的电子物理。这些性质源于二维材料在异质界面处的范德华相互作用。决定异质界面结构响应的一个基本特征是构成它的原子晶格之间的不可通约性或不相容性的程度。然而，量化不可通约性及其对结构反应的影响的问题仍然是一个基本的悬而未决的问题，这将在本项目中进行探讨。这项研究的成功将为应变工程二维材料系统提供理论和计算框架，用于下一代纳米润滑剂、电子和光电子器件等应用。在教育和推广方面，该项目将发展跨学科的STEAM活动，其中艺术和科学相辅相成。这些活动将包括直接与本科生和高中生合作，并与高中教师合作开发以重叠二维原子晶格背后的科学和艺术为中心的学习模块。双晶学对二维材料系统的设计、合成和转移的主要影响，以及利用在宏观尺度上施加的应变来控制局部微观结构的能力，激发了本项目的目标：实现应变工程的全部潜力，作为调节异质界面中原子重建的途径，以获得功能性能。目的是根据界面的微观结构完全表征异质界面对温度、剪切力和法向力的响应。本研究将建立一个统一的框架，其中双晶学将成为探索不可通约性的结构响应如何在界面位错行为中表现出来的中心舞台。双晶体学将使用像史密斯范式这样的代数工具来揭示异质界面的平移对称性并表征其界面位错。应变和衬底工程将通过在连续体和中尺度上对界面位错和衬底晶格步骤进行建模来实现。该结果将导致对结构性质如何从范德华相互作用中产生的新理解，并为异质结构的系统设计和大规模合成铺平道路。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。

This Faculty Early Career Development (CAREER) award will support research to explore how strain can be used to study the structural response of heterointerfaces for the design and synthesis of atomically thin two-dimensional materials systems. Heterostructures formed by stacking distinct two-dimensional materials demonstrate exceptional mechanical and electronic properties, such as superlubricity, high strain tolerance, and correlated electronic physics. These properties originate from the van der Waals interactions at the heterointerfaces formed by the two-dimensional materials. A fundamental feature that dictates the structural response of a heterointerface is the degree of incommensurability or incompatibility between the atomic lattices that form it. However, the problem of quantifying incommensurability and its effect on the structural response remains a fundamental open question, which will be explored in this project. The success of this study will lead to a theoretical and computational framework to strain engineer two-dimensional materials systems for applications such as next generation nanolubricants and electronic and optoelectronic devices. On the education and outreach front, the project will develop transdisciplinary STEAM activities wherein Art and Science complement each other. These activities will involve working directly with undergraduate and high school students and collaborating with high school teachers to develop learning modules centered around the science and art behind overlapping two-dimensional atomic lattices. The dominant influence of bicrystallography on the design, synthesis, and transfer of two-dimensional materials systems and the ability to control the local microstructure using strain applied at the macroscale motivate this project's goal: to realize the full potential of strain engineering as a route to modulate the atomic reconstruction in heterointerfaces for functional performance gains. The objective is to completely characterize the response of heterointerfaces to temperature and shear and normal forces in terms of the interface's microstructure. This study will develop a unified framework wherein bicrystallography takes center stage to explore how a structural response to incommensurability manifests in interfacial dislocation behavior. Bicrystallography will be examined using algebraic tools like the Smith normal form to reveal the translational symmetry of the heterointerfaces and characterize their interface dislocations. Strain and substrate engineering will be realized by the modeling of interface dislocations and substrate lattice steps at the continuum and mesoscale. The outcome will lead to a new understanding of how structural properties emerge from van der Waals interactions and pave the way for a systematic design and large-scale synthesis of heterostructures.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.