Many-body interactions in monolayer transition-metal dichalcogenides are strongly affected by their unique band structure. We study these interactions by measuring the energy shift of neutral excitons (bound electron-hole pairs) in gated WSe2 and MoSe2. Surprisingly, while the blueshift of the neutral exciton, X0, in electron-doped samples can be more than 10~meV, the blueshift in hole-doped samples is nearly absent. Taking into account dynamical screening and local-field effects, we present a transparent and analytical model that elucidates the crucial role played by intervalley plasmons in electron-doped conditions. The energy shift of X0 as a function of charge density is computed showing agreement with experiment, where the renormalization of X0 by intervalley plasmons yields a stronger blueshift in MoSe2 than in WSe2 due to differences in their band ordering.
@article{arxiv.1606.07101,
title = {Probing Many-Body Interactions in Monolayer Transition-Metal Dichalcogenides},
author = {Dinh Van Tuan and Benedikt Scharf and Zefang Wang and Jie Shan and Kin Fai Mak and Igor Zutic and Hanan Dery},
journal= {arXiv preprint arXiv:1606.07101},
year = {2019}
}
Comments
Compared with the previous version, this is an entirely new paper except for the experiment part. It took us 2 more years to get the theory straight and we hope it is right this time