Professor Jyoti Katoch
Carnegie Mellon University
Probing Highly Tunable Electronic Properties of Layered Quantum Materials
Location: 1080 Physics Research Building
Faculty Host: Fengyuan Yang
Abstract: Extreme surface sensitivity of two-dimensional (2D) materials provides an unprecedented opportunity to engineer the physical properties of these materials via changes to their surroundings, including substrate, adsorbates, defects, etc. In addition, 2D materials can be mechanically assembled layer-by-layer to form vertical or lateral heterostructures, making it possible to create novel material properties merely by the choice of the constituting 2D layers. For instance, van der Waals (vdW) heterostructures with a twist angle between the constituent layers, provide ability to create nanoscale perturbations that have shown to give rise to coexisting complex phases of matter including Mott insulating state, superconductivity, bound quasiparticles, and topological states. The advent of the state-of-the-art angle-resolved photoemission spectroscopy with nanoscale spatial resolution (nanoARPES) and the ability to perform these measurements on fully functional devices, has made it possible to directly probe many exotic physical phenomena in 2D based material systems. In this talk, I will present our work on directly visualizing (without any assumption) the electronic properties in vdW materials utilizing the cutting edge in-operando nanoARPES on 2D heterostructures and their fully functional devices. I will present the experiments which demonstrate on-demand tuning of the electronic band structure in atomically thin systems, such as transition metal dichalcogenides (TMDs) and graphene, by varying the twist-angle between the atomic layers and external dopants. Specifically, I will discuss the electric field tuning of the electronic interactions that result in van Hove singularity and flat bands in twisted bilayer graphene and twisted double bilayer graphene heterostructures. Also, I will show our recent results where we observe the formation of quasiparticle polarons due to many-body interactions in graphene/TMD heterostructures.
Bio: Jyoti Katoch received her PhD in Physics from University of Central Florida (UCF). She was a postdoc at the Ohio State University in the research groups of Roland Kawakami and Marc Bockrath. Later she was a Research Scientist at the Center for Emergent Materials: an NSF-MRSEC at the Ohio State University. She joined as an Assistant Professor in the physics department at Carnegie Mellon University (CMU) in 2018. Her research group primarily focuses on creation of emergent quantum materials and studying their electronic properties employing in-operando focused photoemission spectroscopy techniques on fully functional devices. She is a recipient of the Ralph E. Powe Junior Faculty Enhancement Award, Department of Energy Early Career Award, and National Science Foundation Early Career Award. She has served in leadership roles including founding president of Women in Physics Society at UCF, Chair of Conference for Undergraduate Women in Physics at CMU, and currently serving as Chair of the 2D technical group at the American Vacuum Society.
