Speaker
Description
Interlayer excitons (IX)—electron-hole pairs spatially separated between two layers of two-dimensional materials—have gained attention for their potential to enable the exploration of novel bosonic quantum phases and Bose-Fermi mixtures. A promising route to stabilize IXs is to use transition metal dichalcogenide (TMD) bilayers seperated by thin hexagonal boron nitride (hBN), which isolates itinerant electrons and holes. While these systems have primarily been studied through transport measurements, challenges such as difficulties in making ohmic contacts to TMD monolayers and the lack of photoluminescence have limited their broader exploration.
Here, we demonstrate the optical generation of IXs in bilayer TMD heterostructures separated by up to seven hBN layers. Remarkably, the 2s excitons in each layer persist in the presence of opposite charges, indicating strong binding into stable interlayer excitons. We measure lifetimes up to eight µs, highlighting the potential of these excitons for exploring exotic quantum phases, such as Bose-Fermi mixtures and excitonic condensates. These phenomena can be efficiently probed using optical spectroscopy, paving the way for future studies.
