Quantitative determination of interlayer electronic coupling at various critical points in bilayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Mo</mml:mi><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Wei‐Ting Hsu, Jiamin Quan, Chi-Ruei Pan, Peng-Jen Chen, M. Y. Chou, Wen‐Hao Chang, A. H. MacDonald, Xiaoqin Li, Jung‐Fu Lin, Chih‐Kang Shih
Abstract
Tailoring interlayer coupling has emerged as a powerful tool to tune the electronic structure of van der Waals (vdW) bilayers. One example is the usage of the ``moir\'e pattern'' to create controllable two-dimensional electronic superlattices through the configurational dependence of interlayer electronic couplings. This approach has led to some remarkable discoveries in twisted graphene bilayers, and transition metal dichalcogenide homo- and heterobilayers. However, a largely unexplored factor is the interlayer distance $d$, which can impact the interlayer coupling strength exponentially. In this paper, we quantitatively determine the coupling strengths as a function of interlayer spacing at various critical points of the Brillouin zone in bilayer $\mathrm{Mo}{\mathrm{S}}_{2}$. The exponential dependence of the coupling parameter on the gap distance is demonstrated. Most significantly, we achieved a 280% enhancement of $K\text{\ensuremath{-}}\mathrm{valley}$ coupling strength with an 8% reduction of the vdW gap, pointing to a strategy for designing a unique electronic system in vdW bilayers.