Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 66: 2D Materials IV: Interfacial Interactions (joint session O/CPP/HL)

O 66.5: Talk

Wednesday, March 18, 2020, 11:30–11:45, WIL B321

Screening effects at the internal interfaces of bulk-like MoS₂ — •Philipp Marauhn, Peter Krüger, and Michael Rohlfing — Institut für Festkörpertheorie, Westfälische Wilhelms-Universität, 48149 Münster, Germany

The two-dimensional nature of TMDCs is intrinsically linked to reduced screening. This renders the materials sensitive to their dielectric environment. Quasiparticle calculations of MoS₂ deposited on different substrates have shown the importance to account for environmental screening [1]. In this talk we discuss how screening effects modify the electronic structure across the internal interfaces of bulk-like MoS₂.

In a first step we use a tight-binding model to reproduce the band structure on a level of density functional theory. To include polarization effects, we extend the model by introducing a self-energy operator constructed from layer-resolved quasiparticle corrections calculated within the framework of GW. Using this GW-tight-binding approach, we show that environmental screening has strong impact on the formation of the subbands which originate from interlayer interactions. Most striking, at the K-point, the surface layer decouples from lower lying layers forming a direct gap which is distinctly different from that of the total system.

[1] M. Drüppel et al., Nat. Commun. 8(1), 2117 (2017)