CAREER: Modulation of the Interlayer Coupling in Heterostructures based on Two-Dimensional Materials

Auburn University, Auburn AL

Investigators

Abstract

NONTECHNICAL SUMMARY This CAREER award supports computational and theoretical research and education on materials which are composed of stacked two-dimensional layers and exhibit novel properties and phenomena. Each layer consists of few-atom-thick crystals, which are particularly interesting due to the differences between their in-plane and out-of-plane properties, and the capability to stack them. These properties can be tuned through external mechanical, electrical, or magnetic fields. Theoretical descriptions of the properties of these materials do not include atomic-scale details; this makes it difficult to identify underlying principles to control their behavior and to devise corresponding control mechanisms. Elucidating the interplay among weak interactions, structure, and function in these materials called layered heterostructures is key to the discovery of novel physical phenomena. The PI will use computational methods to study these materials with the aim to help accelerate the deployment of functional high-performance materials and energy-efficient platforms that can revolutionize electronic and sensing device technologies. Inspired by recent experiments demonstrating the modulation of electron tunneling in heterostructures based on two-dimensional materials, the PI will combine theoretical models and state-of-the-art computation to describe novel physical phenomena emerging in these systems. In particular, this project is aimed to investigate how interlayer coupling can be tuned by using external fields in two-dimensional materials. Understanding the quantitative relationship between interlayer coupling and the atomistic details of these material systems will enable a data-driven search for other complex structures where key properties are enhanced, and guide design and experimental realization of new materials with promising properties. This research will be coupled to education and outreach activities to be carried out at Auburn University and in the Southeastern US region. The PI will create a webinar series on various areas of physics targeting broad undergraduate student audiences in universities and colleges throughout the Southeastern US region. In these webinars, faculty from different institutions will discuss current directions of their research areas and disseminate potential opportunities for graduate studies or research experiences. The PI and his group will be actively involved in two existing and successful outreach programs at Auburn University for middle and high school students: The Summer Science Institute and the Semiconductor Day. The PI will develop student-centered course curricula pertaining to novel physics emerging at the nanoscale and electronic structure. TECHNICAL SUMMARY This CAREER award supports computational and theoretical research and education on multilayer heterostructures formed with two-dimensional materials. This family of materials consists of few-atom-thick crystals, which are particularly attractive due to their highly anisotropic properties and the capability to stack them without restrictions found in bulk systems. The strength of the interlayer coupling in these systems is comparable to energy scales induced through external electric, magnetic, and mechanical fields. So, these complex heterostructures offer the possibility of unprecedented modulation of the interlayer coupling with consequences for their properties. Theoretical descriptions of these interactions have so far relied on phenomenological lumped models that do not include atomistic details or quantum mechanical effects which makes it challenging to identify underlying principles and devise mechanisms to control their functionalities. Elucidating the interplay among weak interactions, structure, and function in these heterostructures is key to fully exploit their potential and expand the repertoire of functional materials and a goal of this project. The research will combine theoretical models, first principles calculations, and large-scale computation to describe the weak interactions in heterostructures based on two-dimensional materials including atomistic details and quantum mechanical effects. First, the PI and his team will investigate modulation of the interlayer coupling via external electric, magnetic, and mechanical fields in two-dimensional materials and their alloys. Next, the PI will use state-of-the-art high-throughput computations to enable a data-driven search of heterostructures formed with different two-dimensional materials that exhibit enhanced properties of particular interest. The result will serve as a guide to experimental design. This integrated theoretical-computational approach to the characterization of complex heterostructures may translate into the discovery of novel physical phenomena. In addition, it may help to accelerate the deployment of functional high-performance materials and energy-efficient device structures that can revolutionize electronic device and sensor technologies. This research will be coupled to education and outreach activities to be carried out at Auburn University and in the Southeastern US region. The PI will create a webinar series on various areas of physics targeting broad undergraduate student audiences in universities and colleges throughout the Southeastern US region. In these webinars, faculty from different institutions will discuss current directions of their research areas and disseminate potential opportunities for graduate studies or research experiences. The PI and his group will be actively involved in two existing and successful outreach programs at Auburn University for middle and high school students: The Summer Science Institute and the Semiconductor Day. The PI will develop student-centered course curricula pertaining to novel physics emerging at the nanoscale and electronic structure. This project is jointly funded by the Division of Materials Research through the Condensed Matter and Materials Research Program, and the Established Program to Stimulate Competitive Research (EPSCoR). 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.