We investigate the origin of emission lines apparent in the low-temperature photoluminescence spectra of n-doped WS2 monolayer embedded in hexagonal BN layers using external magnetic fields and first-principles calculations. Apart from the neutral A exciton line, all observed emission lines are related to the negatively charged excitons. Consequently, we identify emissions due to both the bright (singlet and triplet) and dark (spin- and momentum-forbidden) negative trions as well as the phonon replicas of the latter optically-inactive complexes. The semi-dark trions and negative biexcitons are distinguished. Based on their experimentally extracted and theoretically calculated g-factors, we identify three distinct families of emissions due to exciton complexes in WS2: bright, intravalley and intervalley dark. The g-factors of the spin-split subbands in both the conduction and valence bands are also determined.
@article{arxiv.2012.11509,
title = {Excitonic complexes in $n$-doped WS$_2$ monolayer},
author = {M. Zinkiewicz and T. Woźniak and T. Kazimierczuk and P. Kapuściński and K. Oreszczuk and M. Grzeszczyk and M. Bartos and K. Nogajewski and K. Watanabe and T. Taniguchi and C. Faugeras and P. Kossacki and M. Potemski and A. Babiński and M. R. Molas},
journal= {arXiv preprint arXiv:2012.11509},
year = {2021}
}