Nonmonotonous Distance Dependence of van der Waals Screening by a Dielectric Layer.

Van der Waals (vdW) screening or Faraday-cage-like screening of vdW interaction by monolayer crystals has recently been observed in experiments and understood from first-principles theories. Here, we investigate the vdW screening by a bulky dielectric layer using the Lifshitz theory. The ratio of vdW screening is found to depend on not only the interobject distance but also the thicknesses of the separated layers. Surprisingly, the screening ratio exhibits a nonmonotonous distance dependence, first increasing, but beyond a critical distance reducing, toward zero. The short-range trend coincides with that predicted for graphene-like trilayers by the random phase approximation, while the long-range trend poses a contrast to the increasing screening with distance by graphene predicted by the many-body dispersion approach. The positive correlation between the screening ratio and the dielectric constant revealed for atomistic layers is reproduced for the bulky dielectric layers.