  From monolayers composed of different atoms, we can build structures with
spontaneous vertical polarization by conveniently stacking multiple layers. We
have studied, using first-principles methods and based on modern polarization
theory, a system composed of three layers of hexagonal Boron-Nitride(h-BN) in
all possible stackings. We obtain for each of the configurations how charge
transfers between the layers and how it impacts on the polarization of the
system. In addition, we studied a system of three layers, one of them rotated,
and we found that not only did the magnitude of the polarization increase
comparing with the bilayer but also, depending on the initial stacking and the
rotated layer, we can create a variety of mosaic-like polarization
arrangements, which are composed of regions with either triangular or hexagonal
symmetry.
