Dr. Elisa Riedo, Professor of Physics at the City University of New York’s Advanced Science Research Center (ASRC), and a team of international scientists recently investigated the interaction between atomically thin layers in two-dimensional materials, the study of which appeared in June in Nature Materials magazine.
“Researchers are seeking to understand two-dimensional materials because of their potential in nanotechnology applications,” Riedo said. “Two-dimensional (2D) materials, such as epitaxial graphene and MoS2, are films made of a few layers, where each layer is only one atom thick. These films are characterized by strong in-plane bonds and weak interactions between the layers. The coupling between layers is key because it determines the thermal, electronic, tribological and optical properties of these films.”
The article, “Elastic coupling between layers in two-dimensional materials”, reported on extremely sensitive measurements where sub-angstrom-resolution indentations are used to measure the perpendicular-to-the-plane elasticity of 2D materials. The in-plane elasticity of these materials has been widely studied in the past; however, little was known about the films’ elastic modulus perpendicular to the planes, as these types of measurements require ultra-small indentations.
Riedo and her collaborators were then able to measure and control indentation depths smaller than the films’ interlayer distance. Furthermore, by combining experiments with density functional theory calculations of Dr. Angelo Bongiorno — fellow principal investigator and professor of chemistry at CUNY’s College of Staten Island — the team was able to tune the interlayer elasticity by water molecule intercalation.
“What is particularly powerful about this methodology is its’ ability to create a direct link between structure and properties of 2D materials — which will be of use in design of functional 2D materials for a variety of applications,” said Nanoscience Initiative Director Dr. Rein Ulijn. “We are excited to have this unique capability available within the ASRC.”
Riedo, who recently joined the ASRC’s Nanoscience Initiative and also holds a professorship at The City College of New York, began the study in her previous faculty position at the Georgia Institute of Technology. The Office of Basic Energy Sciences of the US Department of Energy Support (DE-FG02-06ER46293) provided support for the study.
About the ASRC: The new CUNY Advanced Science Research Center (ASRC) is a University-wide venture that elevates CUNY’s legacy of scientific research and education through initiatives in five distinctive, but increasingly interconnected disciplines: Nanoscience, Photonics, Structural Biology, Neuroscience and Environmental Sciences. Led by Dr. Gillian Small, Vice Chancellor for Research and the ASRC’s executive director, the center is designed to promote a unique, interdisciplinary research culture. Researchers from each of the initiatives work side by side in the ASRC’s core facilities, sharing equipment that is among the most advanced available. Funding for the ASRC from New York State is gratefully acknowledged.