Speaker
Description
Monolayers of Transition Metal Dichalcogenides (TMDs) have become a central focus in condensed matter physics research due to their exceptional optoelectronic properties, which arise from strong light-matter interactions. Quantum confinement and reduced Coulomb screening make TMDs an ideal system for studying excitons (i.e. ground state and excited state excitons) and their many-body complexes (i.e. trions, biexcitons, and other multiparticle states), as well as exploring their tunability in response to external factors like electric and magnetic fields, or lattice strain. Furthermore, the ability to optically control and manipulate the spin/valley degree of freedom has significantly amplified interest in these materials. The possibility to stack two or more TMD layers and form vertical 2D heterostructures hosting long-lived interlayer excitons further enrich the excitons physics of these materials.
Since the advent of 2D materials, out-of-equilibrium spectroscopies have been extensively used to study the mechanisms of formation, relaxation, and recombination of excitons occurring on different timescales, ranging from tens of femtoseconds to nanoseconds.
Here, I will exploit helicity resolved broadband pump-probe optical spectroscopy to study valley-resolved exciton dynamics in monolayers TMD focusing on intervalley coupling dynamics between excitons, valley depolarization mechanisms and inter/intravalley biexcitons. The second part of the talk will be devoted to the study of exciton/carrier dynamics in TMD heterobilayers and hybrid TMD/halide perovskite heterostructures.