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

Howard University, Washington DC

Investigators

Abstract

NONTECHNICAL SUMMARY This 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 SUMMARY This 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.