Optical Spectrum of MoS 2 : Many-Body Effects and Diversity of Exciton States

We present first-principles calculations of the optical response of monolayer molybdenum disulfide employing the $GW$-Bethe-Salpeter equation ($GW$-BSE) approach including self-energy, excitonic, and electron-phonon effects. We show that monolayer ${\mathrm{MoS}}_{2}$ possesses a large and diverse number of strongly bound excitonic states with novel $k$-space characteristics that were not previously seen experimentally or theoretically. The absorption spectrum is shown to be dominated by excitonic states with a binding energy close to 1 eV and by strong electron-phonon broadening in the visible to ultraviolet range. Our results explain recent experimental measurements and resolve inconsistencies between…