PME Distinguished Colloquium Series Seminar: Abhay Pasupathy, Columbia University

Two-dimensional semiconductors feature a host of unique electrodynamical phenomena that have been

probed extensively with light. Among the many unique characteristics of these materials is the fact that electromagnetic fields can strongly modify the single-particle electronic properties such as the electronic bandgap of the material. In this presentation, I will describe new instrumentation to probe the electronic structure of 2D semiconductors under intense light fields. We achieve this by integrating a scanning tunneling microscope with a near-field optical microscope based on a tapered optical fiber. I will show how the tunneling gap and other single-particle properties of monolayer transition metal dichalcogenide semiconductors can be sensitively tuned by the illumination intensity. I will also show the utility of the instrumentation to detect localized emission from nanostructured surfaces with sub-10 nm spatial resolution.