Ultralow Auger-Assisted Interlayer Exciton Annihilation in WS<sub>2</sub>/WSe<sub>2</sub> Moiré Heterobilayers.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38285707.
- Also identified by DOI 10.1021/acs.nanolett.3c04688 and PMC identifier 10921466.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Transition metal dichalcogenide (TMD) heterobilayers have emerged as a promising platform for exploring solid-state quantum simulators and many-body quantum phenomena. Their type II band alignment, combined with the moiré superlattice, inevitably leads to nontrivial exciton interactions and dynamics. Here, we unveil the distinct Auger annihilation processes for delocalized interlayer excitons in WS<sub>2</sub>/WSe<sub>2</sub> moiré heterobilayers. By fitting the characteristic efficiency droop and bimolecular recombination rate, we quantitatively determine an ultralow Auger coefficient of 1.3 × 10<sup>-5</sup> cm<sup>2</sup> s<sup>-1</sup>, which is >100-fold smaller than that of excitons in TMD monolayers. In addition, we reveal selective exciton upconversion into the WSe<sub>2</sub> layer, which highlights the significance of intralayer electron Coulomb interactions in dictating the microscopic scattering pathways. The distinct Auger processes arising from spatial electron-hole separation have important implications for TMD heterobilayers while endowing interlayer excitons and their strongly correlated states with unique layer degrees of freedom.