Twist-induced interlayer charge buildup in a WS2 bilayer revealed by electron Compton scattering and density functional theory

Talmantaite, A.; Xie, Y.; Cohen, A.; Mohapatra, P.K.; Ismach, A.; Mizoguchi, T.; Clark, S.J.; Mendis, B.G.

Abstract

Exotic properties emerge from the electronic structure of few-layer transition-metal dichalcogenides (TMDs), such as direct band gaps in monolayers and moiré excitons in twisted bilayers, which are exploited in modern optoelectronic devices and twistronics. Here, Compton scattering in a transmission electron microscope (TEM) is used to probe the nature of the interlayer electronic coupling in the TMD material W S 2 . The high spatial resolution and strong scattering in the TEM enables a complete analysis of individual W S 2 domains, including their crystal structure. Compton measurements show that the electrons in an 18 ∘ twisted bilayer are more localized than in a monolayer. Density functional theory simulations reveal this is caused by a twist-induced charge buildup in the interlayer region, directly shielding the energetically unfavorable overlapping tungsten atoms. This unexpected result uncovers the precise role of twist angle on interlayer coupling, and therefore the physical properties that depend on it.

Citation

Talmantaite, A., Xie, Y., Cohen, A., Mohapatra, P., Ismach, A., Mizoguchi, T., …Mendis, B. (2023). Twist-induced interlayer charge buildup in a WS2 bilayer revealed by electron Compton scattering and density functional theory. Physical Review B, 107(23), Article 235424. https://doi.org/10.1103/physrevb.107.235424

• Journal Article Type: Article
• Acceptance Date: Jun 13, 2023
• Online Publication Date: Jun 27, 2023
• Publication Date: Jun 15, 2023
• Deposit Date: Jul 3, 2023
• Publicly Available Date: Jul 3, 2023
• Journal: Physical review B: Condensed matter and materials physics
• Print ISSN: 2469-9950
• Electronic ISSN: 2469-9969
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 107
• Issue: 23
• Article Number: 235424
• DOI: https://doi.org/10.1103/physrevb.107.235424