Scaleability of dielectric susceptibility εzz with the number of layers and additivity of ferroelectric polarization in van der Waals semiconductors

We study the dielectric response of few layered crystals of various\ntransition metal dichalcogenides (TMDs) and hexagonal Boron Nitride (hBN). We\nshowed that the out-of-plane polarizability of a multilayer crystal (which\ncharacterizes response to the external displacement field) scales linearly with\nthe number of layers, $\\alpha_{zz}^{NL} =N \\alpha_{zz}^{1L}$, independently of\nthe stacking configuration in the film. We also established additivity of\nferroelectric polarizations of consecutive interfaces in case when such\ninterfaces have broken inversion symmetry. Then we used the obtained data of\nmonolayer $\\alpha_{zz}^{1L}$ to calculate the values of the dielectric\nsusceptibilities for semiconductor TMDs and hBN bulk crystals.\n