Dielectric screening by 2D substrates

摘要: Two-dimensional (2D) materials are increasingly being used as active components in nanoscale devices. Many interesting properties of 2D stem from the reduced and highly non-local electronic screening two dimensions. While within has been studied extensively, question still remains how substrates screen charge perturbations or excitations adjacent to them. Thickness-dependent dielectric have recently using electrostatic force microscopy (EFM) experiments. However, it was suggested that some thickness-dependent trends were due extrinsic effects. Similarly, Kelvin probe measurements (KPM) indicate fluctuations when BN slabs placed on SiO2, but is unclear if this effect intrinsic BN. In work, we use first principles calculations study fully material substrates. Our simulations give results good qualitative agreement with those EFM experiments, for hexagonal boron nitride (BN), graphene MoS2, indicating experimentally observed effects materials. We further investigate explicitly role lowering potential arising impurities an underlying SiO2 substrate, KPM can also dramatically change HOMO-LUMO gaps adsorbates, especially small molecules, such benzene. propose a reliable very quick method predict physisorbed molecules 3D substrates, only band gap substrate gas phase molecule.