title: Model dielectric function for 2D semiconductors including substrate screening.
abstract: Dielectric screening of excitons in 2D semiconductors is known to be a highly non-local effect, which in reciprocal space translates to a strong dependence on momentum transfer q. We present an analytical model dielectric function, including the full non-linear q-dependency, which may be used as an alternative to more numerically taxing ab initio screening functions. By verifying the good agreement between excitonic optical properties calculated using our model dielectric function, and those derived from ab initio methods, we demonstrate the versatility of this approach. Our test systems include: Monolayer hBN, monolayer MoS2, and the surface exciton of a 2 × 1 reconstructed Si(111) surface. Additionally, using our model, we easily take substrate screening effects into account. Hence, we include also a systematic study of the effects of substrate media on the excitonic optical properties of MoS2and hBN.
authors.affiliation: Laboratoire des Solides Irradiés, Ecole polytechnique, CNRS, CEA, Université Paris-Saclay, 91128 Palaiseau, France.|European Theoretical Spectroscopy Facility, 91128 Palaiseau, France.
authors.forename: Mads L
authors.initials: ML
authors.lastname: Trolle
authors.affiliation: Department of Physics and Nanotechnology, Aalborg University, DK-9220 Aalborg Øst, Denmark.|Center for Nanostructured Graphene (CNG), DK-9220 Aalborg Øst, Denmark.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Pedersen
authors.affiliation: Laboratoire des Solides Irradiés, Ecole polytechnique, CNRS, CEA, Université Paris-Saclay, 91128 Palaiseau, France.|European Theoretical Spectroscopy Facility, 91128 Palaiseau, France.
authors.forename: Valerie
authors.initials: V
authors.lastname: Véniard