RQS Seminar: Pranshoo Upadhyay

Title:  Giant enhancement of exciton diffusion near an electronic Mott insulator
Speaker:  Pranshoo Upadhyay (JQI)
Date & Time:  May 14, 2026, 11:00am
Where to Attend:  PSC 2136 and Virtual Via Zoom: https://umd.zoom.us/j/94259669724

Bose-Fermi mixtures can be realized in semiconductor heterostructures, with bosons as excitons and fermions as dopant charges. However, the complexity of these hybrid systems challenges understanding of the mechanisms that determine properties such as mobility. We investigated interlayer exciton diffusion in tungsten diselenide–tungsten disulfide heterobilayers at ultralow exciton density and low temperatures to examine how charges affect exciton mobility. Near the electronic Mott insulator phase, we observed a giant thousand-fold enhancement of exciton diffusion relative to charge neutrality. We attribute this to mobile valence holes, which experienced a suppressed moiré potential due to charge order and recombined nonmonogamously with conduction electrons. Our results show exciton diffusion as a probe of correlated electron states and Bose-Fermi interplay.

Lunch will be served after the talk.

*We strongly encourage attendees to use their full name (and if possible, their UMD credentials) to join the zoom session.*