Physics Department Colloquium - Light-Matter Interactions in Zerovalent Metal-Intercalated MoS2 - Professor Ashwin Ramasubramaniam, Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst

The intercalation of layered compounds is a promising route for scalable synthesis of 2D heterostructures with novel emergent optoelectronic properties. Here, we investigate, via first principles calculations, the intercalation of zerovalent metals within the van der Waals gap of bulk MoS2. Specifically, we focus on Cu-MoS2 and Sn-MoS2 hybrids that can accommodate from clusters to uniform, continuous 2D metallic layers of metallic Cu within the vdW gap of MoS2. We study the evolution of the Cu-MoS2 and Sn-MoS2 hybrids with increasing metal content and examine the consequences for intercalation energetics and optoelectronic properties as the intercalated metals evolve from disordered clusters to contiguous layers. We identify emergent interfacial plasmons(1-2 eV range) that are unique to these intercalated materials, arising from resonant 2D metallic states within the MoS2 band gap. Our calculations are shown to be in good agreement with experiments and help explain the enhanced infrared absorption of the Cu-MoS2 and Sn-MoS2 hybrids. Overall, these results indicate that intercalation of zerovalent metals in layered materials offers a facile and scalable approach for designing hybrid 2D heterostructures with tunable optoelectronic properties for device applications.

References 1. Stern, C., Twitto, A., Snitkoff, R. Z., Fleger, Y., Saha, S., Boddapati, L., Jain, A., Wang, M., Koski, K. J., Deepak, F. L., Ramasubramaniam, A., Naveh, D., Enhancing Light–Matter Interactions in MoS2 by Copper Intercalation. Adv. Mater. 2021, 33, 2008779. 2. Twitto, A., Stern, C., Poplinger, M., Perelshtein, I., Saha, S., Jain, A., Koski, K.J., Deepak, F.L., Ramasubramaniam, A. and Naveh, D., Optoelectronics of Atomic Metal–Semiconductor Interfaces in TinIntercalated MoS2. ACS Nano, 2022, 16, 17080.

Biography Ashwin Ramasubramaniam is a Professor in the Department of Mechanical & Industrial Engineering at the University of Massachusetts Amherst and the Director of the Materials Science & Engineering Graduate Program. He received his Ph.D. in the Mechanics of Solids and Structures from Brown University in 2005. Prior to joining the UMass Amherst faculty in 2009, he was a Research Associate in Applied & Computational Mathematics at Princeton University and a Postdoctoral Scholar in Aeronautical Engineering at Caltech. His research interests are at the intersection of materials physics, chemistry and mechanics. Research projects underway in his group include studies of thermomechanical properties of 2D metamaterials, optoelectronic properties of hybrid 2D materials, and computational nanocatalysis.