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arXiv · 1501.02273

Exciton band structure of monolayer MoS2

Fengcheng Wu·Fanyao Qu·A. H. MacDonald
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Abstract

We address the properties of excitons in monolayer MoS$_2$ from a theoretical point of view, showing that low-energy excitonic states occur both at the Brillouin zone center and at the Brillouin-zone corners, that binding energies at the Brillouin-zone center deviate strongly from the $(n-1/2)^{-2}$ pattern of the two-dimensional hydrogenic model, and that the valley-degenerate exciton doublet at the Brillouin-zone center splits at finite momentum into an upper mode with non-analytic linear dispersion and a lower mode with quadratic dispersion. Although monolayer MoS$_2$ is a direct-gap semiconductor when classified by its quasiparticle band structure, it may well be an indirect gap material when classified by its excitation spectra.

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Fengcheng Wu, Fanyao Qu, A. H. MacDonald. 2015-02-16. Exciton band structure of monolayer MoS2. https://doi.org/10.1103/physrevb.91.075310

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