Thickness dependence of the effective dielectric constant in a thin film capacitor

The static value of the effective dielectric constant in a thin film capaci tor is simulated by means of the local field theory. The value of it shows a sharp decrease as the film thickness is decreased in an ultrathin film ge ometry. This phenomenon is due to the size effect intrinsic to a thin film structure and has nothing to do with the material aspect. The decrease is m ore remarkable for larger values of the bulk dielectric constant. It is rec overed by inserting interface layers with larger atomic polarizability betw een the film and the capacitor electrode. (C) 1998 American Institute of Ph ysics. [S0003-6951(98)01031-6].