by Applying Gigapascal High Pressure*

Interlayer electronic and mechanical coupling plays a critical role in determining the novel electronic properties of van der Waal (vdW) bilayers. In particular, the coupling strength is determined by the stacking configuration and the interlayer spacing. While the former has been well established, the influence of interlayer spacing remains largely unexplored. Here, by measuring the optical absorption and Raman mode of the bilayer MoS₂ in a high-pressure diamond anvil cell, we quantitatively determined the coupling strength of the electronic band and phonon mode. All experimental results are supported by theoretical calculations. Our work has confirmed the great potential in tailoring vdW bilayers through gigapascal high pressure.