Join us for a talk titled: Cooperative Emission Dynamics in 2D Quantum Materials

Jan Kumlin is from the Vienna University of Technology, Austria

Abstract:

Two-dimensional semiconductors, such as atomically thin transition-metal dichalcogenides and their moiré heterostructures, have recently emerged as a fascinating platform for exploring the rich many-body physics of electrons and excitons. These heterostructures enable strong light-matter coupling, providing a promising quantum optics platform where the regular arrangement of long-lived excitons leads to cooperative effects and enhanced light-matter interactions. Additionally, the strong exciton-exciton interactions inherent to these systems give rise to significant nonlinear optical phenomena.

In the first part of this talk, I will discuss the cooperative radiance of moiré excitons, which arises from the deep-subwavelength nature of the moiré lattice and strong excitonic interactions. In particular, I will examine the role of static dipole-dipole interactions between interlayer excitons, demonstrating their substantial impact on cooperative optical properties. I will also highlight how doping with electrons allows for direct control of optical cooperativity, such as enabling superradiant dynamics in othersie subradiant excitonic states.

In the second part, I will present recent collaborative work with Ajit Srivastava's group at Emory University. Here, we identify signatures of ferroelectric ordering of excitons near the Mott insulating state in a WSe₂/WS₂ heterobilayer, as revealed through their emission dynamics.

Jan Arlt