▎ 摘　　要

When two dimensional crystals are atomically close, their finite thickness becomes relevant. Using transport measurements, we investigate the electrostatics of two graphene layers, twisted by theta = 22 degrees such that the layers are decoupled by the huge momentum mismatch between the K and K' points of the two layers. We observe a splitting of the zero-density lines of the two layers with increasing interlayer energy difference. This splitting is given by the ratio of single-layer quantum capacitance over interlayer capacitance C-m and is therefore suited to extract C-m. We explain the large observed value of C-m by considering the finite dielectric thickness d(g) of each graphene layer and determine d(g) approximate to 2.6 angstrom. In a second experiment, we map out the entire density range with a Fabry-Perot resonator. We can precisely measure the Fermi wavelength lambda in each layer, showing that the layers are decoupled. Our findings are reproduced using tight-binding calculations.