Localized interlayer excitons (LIXs) in two-dimensional moir\'e superlattices exhibit sharp and dense emission peaks, making them promising as highly tunable single-photon sources. However, the fundamental nature of these LIXs is still elusive. Here, we show the donor-acceptor pair (DAP) mechanism as one of the origins of these excitonic peaks. Numerical simulation results of the DAP model agree with the experimental photoluminescence spectra of LIX in the moir\'e MoSe2/WSe2 heterobilayer. In particular, we find that the emission energy-lifetime correlation and the nonmonotonic power dependence of the lifetime agree well with the DAP IX model. Our results provide insight into the physical mechanism of LIX formation in moir\'e heterostructures and pave new directions for engineering interlayer exciton properties in moir\'e superlattices.
@article{arxiv.2302.13003,
title = {Interlayer donor-acceptor pair excitons in MoSe2/WSe2 moir\'e heterobilayer},
author = {Hongbing Cai and Abdullah Rasmita and Qinghai Tan and Jia-Min Lai and Ruihua He and Disheng Chen and Naizhou Wang and Zhao Mu and Zumeng Huang and Zhaowei Zhang and John J. H. Eng and Yuanda Liu and Yongzhi She and Nan Pan and Xiaoping Wang and Xiaogang Liu and Jun Zhang and Weibo Gao},
journal= {arXiv preprint arXiv:2302.13003},
year = {2023}
}