Ultralow Auger-Assisted Interlayer Exciton Annihilation in WS2/WSe2 Moiré Heterobilayers.
Cheng-Syuan Cai1,2, Wei-Yan Lai1, Po-Hsuan Liu1
1Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
Transition metal dichalcogenide (TMD) heterobilayers exhibit unique Auger annihilation processes for interlayer excitons. These findings reveal an ultralow Auger coefficient, crucial for quantum simulation applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Information Science
Background:
- Transition metal dichalcogenide (TMD) heterobilayers are key for solid-state quantum simulators.
- Moiré superlattices in TMDs create nontrivial exciton interactions and dynamics due to type II band alignment.
Purpose of the Study:
- To investigate Auger annihilation processes in WS2/WSe2 moiré heterobilayers.
- To understand exciton dynamics and interactions within these engineered quantum systems.
Main Methods:
- Analysis of efficiency droop and bimolecular recombination rates.
- Quantitative determination of Auger coefficients through experimental data fitting.
Main Results:
- Discovered distinct Auger annihilation pathways for delocalized interlayer excitons.
- Quantified an ultralow Auger coefficient (1.3 × 10^-5 cm^2 s^-1), over 100 times smaller than in TMD monolayers.
- Observed selective exciton upconversion into the WSe2 layer, influenced by intralayer electron Coulomb interactions.
Conclusions:
- Spatial electron-hole separation in TMD heterobilayers leads to unique Auger processes.
- The ultralow Auger coefficient is significant for developing advanced quantum simulators.
- Interlayer excitons possess unique layer degrees of freedom, impacting strongly correlated states.
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The work...
