CAREER:Understanding the Effects of the Immediate Environment on Intrinsic Properties of 2D Crystals: From Fundamental Science to Real World Applications

这项美国国家科学基金会职业奖支持理论和计算研究，重点关注直接环境对层状二维材料的物理和化学性质的影响。2004年，从一块石墨中提取了一层单原子厚的碳，称为石墨烯。随后又发现了许多其他的二维晶体。这种材料发现的快速阶段是由二维层状晶体的有趣和不寻常的特性所推动的，这些特性与传统的三维晶体有很大的不同，这并不奇怪。此外，这些晶体的不同层可以堆叠成具有独特性能的设计材料。由于它们的表面特性，二维晶体与其直接环境之间的相互作用比块状晶体的类似相互作用更为重要。直接环境可能包括环境气体和基材。这些相互作用可以以不可预测的方式改变二维晶体的不同性质，但大部分仍未被探索。在这个项目中，PI和她的团队将使用最先进的计算方法来研究二维材料与其局部环境之间的相互作用，推动分层材料领域的发展。在这个过程中，他们将对影响二维材料的结构、电子、磁性和光学性质以及物理和化学行为的因素有一个基本的了解。这项研究不仅有利于基础科学，而且有利于相对论电子学、量子计算、高灵敏度传感器等具有社会重要性的技术。在实现该项目的研究目标的同时，PI还将支持和加强霍华德大学的教育活动。PI将指导凝聚态物理和量子化学领域的新一代科学家，以及使用计算技术来研究材料特性。本研究的不同内容也将被纳入本科和研究生的固态物理课程。PI还计划开发并开设一门名为“交流科学的艺术”的课程。本课程将讨论有效和高效地传播科学成果的必要性，这些成果需要传播给更广泛的科学界和公众。此外，为了培养社区的科学文化，PI计划在霍华德大学建立一个名为“前沿科学”的公共讲座系列。该系列讲座将向霍华德大学、所有高中、当地大学和华盛顿特区都会区的周边社区的所有人开放。技术概述：美国国家科学基金会职业奖支持理论和计算研究，重点关注直接环境对层状二维材料的物理和化学性质的影响。新型层状系统的不同性质才刚刚开始被理解，该领域需要详细的原子研究来解释这些材料的功能。由于其本身的性质，明确考虑：(a)二维材料与其基板之间的界面效应，无论是传统的三维还是二维基板，(b)层状材料与其暴露在另一侧的大气之间的界面效应，以及(c)二维层内的缺陷如何改变界面相互作用，反过来，它们本身又因界面而被修改。到目前为止，这些效应在新型层状二维晶体的理论研究中大多被忽视，但有望在确定其性质方面发挥重要作用。使用基于密度泛函理论的计算方法，PI和她的团队将通过明确地包括相关的局部环境来解决我们知识中的这一差距，并因此确定分层结构的性质如何受到它的影响。这些复合材料的涌现特性将有助于理解现有的实验，并将被利用来提出使用二维结构作为构建块的新颖的、技术相关的设备。PI的研究团队将在不同的应用背景下研究这些效应，例如：(a)用于量子技术的层状二维晶体中的量子发射器，(b)用于纳米电子学和下一代电池的过渡金属二硫族化合物的相变特性，以及(c)高选择性和敏感的生化传感器。这样的应用有可能造福社会。在实现该项目的研究目标的同时，PI还将支持和加强霍华德大学的教育活动。PI将指导凝聚态物理和量子化学领域的新一代科学家，以及使用计算技术来研究材料特性。本研究的不同内容也将被纳入本科和研究生的固态物理课程。PI还计划开发并开设一门名为“交流科学的艺术”的课程。本课程将讨论有效和高效地传播科学成果的必要性，这些成果需要传播给更广泛的科学界和公众。此外，为了培养社区的科学文化，PI计划在霍华德大学建立一个名为“前沿科学”的公共讲座系列。该系列讲座将向霍华德大学、所有高中、当地大学和华盛顿特区都会区的周边社区的所有人开放。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。

NONTECHNICAL SUMMARYThis NSF CAREER award supports theoretical and computational research focused on the effects of the immediate environment on physical and chemical properties of layered two-dimensional materials. In 2004, a single-atom thick layer of carbon, called graphene, was extracted from a piece of graphite. Subsequently many other two-dimensional crystals have been discovered. This rapid phase of material discovery has been fueled by the interesting and unusual properties of the two-dimensional layered crystals that are, not surprisingly, very different from those of conventional three-dimensional crystals. In addition, disparate layers of these crystals can be stacked to make designer materials with unique properties. Owing to their surface-only character, the interactions between two-dimensional crystals with their immediate environment become more important than similar interactions for bulk crystals. The immediate environment may include ambient gases and the substrates. These interactions can alter different properties of two-dimensional crystals in unpredictable ways, but have remained mostly unexplored. In this project, the PI and her group will use state-of-the-art computational methods to study interactions between two-dimensional materials and their local environment, advancing the field of layered materials. In the process, they will develop a fundamental understanding of factors influencing the structural, electronic, magnetic and optical properties and hence, the physical and chemical behavior of two-dimensional materials. This research will benefit not only basic science, but also technologies of societal importance such as, relativistic electronics, quantum computing, and highly sensitive sensors. While pursuing the research goals for this project, the PI will also support and enhance educational activities at the Howard University. The PI will mentor a new generation of scientists in Condensed Matter Physics and Quantum Chemistry, as well as in the use of computational techniques for investigating material properties. Different elements of this research will also be incorporated in the Solid-State Physics courses for undergraduate and graduate students. The PI also plans to develop and offer a course called, "The Art of Communicating Science". This course will address the need to effectively and efficiently communicate scientific results, which need to be disseminated to the broader scientific community and the general public. Further, in order to cultivate the scientific culture in the community, the PI plans to establish a public lecture series at Howard University called "Cutting Edge Science". This lecture series will be open to everyone in Howard University, all high schools, local universities and the surrounding community in the DC metro area. TECHNICAL SUMMARYThis NSF CAREER award supports theoretical and computational research focused on the effects of the immediate environment on physical and chemical properties of layered two-dimensional materials. Different properties of novel layered systems are only beginning to be understood and the field requires detailed atomistic studies to explain the functionalities of these materials. Due to their very nature, it is important to explicitly consider: (a) interfacial effects between two-dimensional materials and their substrates, whether conventional three-dimensional or two-dimensional substrates on one side, (b) interfacial effects between layered-materials and the atmosphere to which they are exposed on the other side, and (c) how defects within the two-dimensional layers alter the interfacial interactions, and in turn, are themselves modified due to the interfaces. These effects have, thus far, been mostly overlooked in theoretical studies of novel layered two-dimensional crystals, but are expected to play an important role in determining their properties. Using Density Functional Theory-based computational methods, the PI and her team will address this gap in our knowledge by explicitly including the relevant local environment, and will therefore determine how the properties of layered structures are affected by it. The emergent properties from these composites will help to understand existing experiments and will be exploited to propose novel, technologically-relevant devices using two-dimensional structures as building blocks. The PI's research team will study these effects in context of different applications, such as: (a) quantum emitters in layered two-dimensional crystals for quantum technologies, (b) phase-change properties of transition metal dichalcogenides for nanoelectronics and next-generation batteries, and (c) highly-selective and sensitive biochemical sensors. Such applications have potential to benefit society. While pursuing the research goals for this project, the PI will also support and enhance educational activities at the Howard University. The PI will mentor a new generation of scientists in Condensed Matter Physics and Quantum Chemistry, as well as in the use of computational techniques for investigating material properties. Different elements of this research will also be incorporated in the Solid-State Physics courses for undergraduate and graduate students. The PI also plans to develop and offer a course called, "The Art of Communicating Science". This course will address the need to effectively and efficiently communicate scientific results, which need to be disseminated to the broader scientific community and the general public. Further, in order to cultivate the scientific culture in the community, the PI plans to establish a public lecture series at Howard University called "Cutting Edge Science". This lecture series will be open to everyone in Howard University, all high schools, local universities and the surrounding community in the DC metro area.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.