Dielectric Screening by 2D Substrates

Abstract

Two-dimensional (2D) materials are increasingly being used as active components in nanoscale devices. Many interesting properties of 2D materials stem from the reduced and highly non-local electronic screening in two dimensions. While electronic screening within 2D materials has been studied extensively, the question still remains of how 2D substrates screen charge perturbations or electronic excitations adjacent to them. Thickness-dependent dielectric screening properties have recently been studied using electrostatic force microscopy (EFM) experiments. However, it was suggested that some of the thickness-dependent trends were due to extrinsic effects. Similarly, Kelvin probe measurements (KPM) indicate that charge fluctuations are reduced when BN slabs are placed on SiO${}_2$, but it is unclear if this effect is due to intrinsic screening from BN. In this work, we use first principles calculations to study the fully non-local dielectric screening properties of 2D material substrates. Our simulations give results in good qualitative agreement with those from EFM experiments, for hexagonal boron nitride (BN), graphene and MoS${}_2$, indicating that the experimentally observed thickness-dependent screening effects are intrinsic to the 2D materials. We further investigate explicitly the role of BN in lowering charge potential fluctuations arising from charge impurities on an underlying SiO${}_2$ substrate, as observed in the KPM experiments. 2D material substrates can also dramatically change the HOMO-LUMO gaps of adsorbates, especially for small molecules, such as benzene. We propose a reliable and very quick method to predict the HOMO-LUMO gap of small physisorbed molecules on 2D and 3D substrates, using only the band gap of the substrate and the gas phase gap of the molecule.

24 pages, 5 figures, Supplementary Information

References in corpus (25)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Boron nitride substrates for high-quality graphene electronics
• Optimized norm-conserving Vanderbilt pseudopotentials
• The GW method
• Optical Spectrum of MoS${}_2$: Many-body Effects and Diversity of Exciton States
• Optimization Algorithm for the Generation of ONCV Pseudopotentials
• BerkeleyGW: A Massively Parallel Computer Package for the Calculation of the Quasiparticle and Optical Properties of Materials and Nanostructures
• Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane
• Screening and Many-Body Effects in Two-Dimensional Crystals: Monolayer MoS${}_2$
• Truncation of Periodic Image Interactions for Confined Systems
• How dielectric screening in two-dimensional crystals affects the convergence of excited-state calculations: Monolayer MoS${}_2$
• Excitons in van der Waals heterostructures: The important role of dielectric screening
• Surface Potentials and Layer Charge Distributions in Few-Layer Graphene Films
• Polarization-induced renormalization of molecular levels at metallic and semiconducting surfaces
• Coulomb-hole summations and energies for GW calculations with limited number of empty orbitals: a modified static remainder approach
• Electric field screening in atomically thin layers of MoS2: the role of interlayer coupling
• Dielectric Screening in Atomically Thin Boron Nitride Nanosheets
• Interlayer coupling and gate-tunable excitons in transition metal dichalcogenide heterostructures
• Non-uniform sampling schemes of the Brillouin zone for many-electron perturbation-theory calculations in reduced dimensionality
• Screening in 2D: GW calculations for surfaces and thin films using the repeated-slab approach
• Mechanism for puddle formation in graphene
• The missing ingredient in effective-medium theories: Standard deviations

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