Quantitative determination of interlayer electronic coupling at various critical points in bilayer MoS2

TL;DR

This paper quantitatively analyzes how interlayer distance affects electronic coupling in bilayer MoS2, revealing an exponential relationship and demonstrating a method to significantly enhance coupling strength by reducing interlayer spacing.

Contribution

It provides the first quantitative analysis of interlayer coupling dependence on distance in bilayer MoS2, highlighting a new approach to tune electronic properties.

Findings

Coupling strength exponentially depends on interlayer distance.

280% increase in K-valley coupling with 8% reduction in vdW gap.

Interlayer distance is a key factor in electronic property tuning.

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 moire 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 (TMD) homo- and hetero-bilayers. However, a largely unexplored factor is the interlayer distance, d, which can impact the interlayer coupling strength exponentially. In this letter, we quantitatively determine the coupling strengths as a function of interlayer spacing at various critical points of the Brillouin zone in bilayer MoS2. The exponential dependence of the coupling parameter on the gap distance is demonstrated. Most significantly, we achieved a 280% enhancement of K-valley coupling strength with an 8% reduction of the vdW gap, pointing to a new strategy in designing a novel electronic system in vdW bilayers.