CM-AMO Seminar | Visualization of Tunable Electronic Structure of Van der Waals Heterostructures

Van der Waals (vdW) heterostructures offer an unprecedented platform for engineering the physical properties of two-dimensional (2D) materials through control of twist angle, strain, and environmental interactions. The advent of state-of-the-art angle-resolved photoemission spectroscopy with nanoscale spatial resolution (nanoARPES), combined with its ability to probe fully functional devices, has opened new avenues for directly visualizing exotic electronic phenomena in these systems. In this talk, I will present our work leveraging cutting-edge in-operando nanoARPES to directly map the electronic properties of vdW heterostructures and their functional devices. I will highlight experiments that demonstrate on-demand tuning of the electronic structure by varying the substrate, twist angle, alkali metal doping, and applying an electric field. First, I will discuss the formation of quasiparticle-like trions and polarons arising from strong many-body interactions in transition metal dichalcogenide (TMD)-based heterostructures. Next, I will present our recent findings on the electronic structure of bilayer graphene on two distinct insulating substrates—hBN and RuCl₃—revealing intriguing new features. Time permitting, I will also show how electric field tuning can modulate electronic interactions, leading to van Hove singularities and flat bands in twisted bilayer graphene and twisted double bilayer graphene heterostructures.

Bio:
Jyoti Katoch is an Associate Professor in the Department of Physics at Carnegie Mellon University. She earned her Ph.D. in Physics from the University of Central Florida in 2014 before joining The Ohio State University as a postdoctoral researcher with Roland Kawakami. In 2016, she was appointed as a Research Scientist at the Center for Emergent Materials, an NSF-MRSEC at The Ohio State University.

In 2018, she joined Carnegie Mellon University as an Assistant Professor, where her research group focuses on the creation of emergent quantum materials and the study of their electronic properties using in-operando focused photoemission spectroscopy techniques on fully functional devices. She is an elected executive member and past program chair (2024) of 2D Materials Technical Group at the American Vacuum Society. She is also a recipient of several prestigious awards, including the Ralph E. Powe Junior Faculty Enhancement Award (2019), the Department of Energy Early Career Award (2019), and the National Science Foundation Early Career Award (2024).