Surface Effects on Dielectric Susceptibility of a Semi-infinite Ferroelectric

The profile of susceptibility near the surface of a semi-infinite ferroelectric is calculated from Landau free energy. In surface ferroelectric phase, the susceptibility is reduced at surface for| δ | << β and much enhanced for| δ | similar β , where δ and β are the extrapolation length and the coherent length respectively. In ferroelectric phase, the surface susceptibility is generally reduced for δ < 0. But the curve is not monotonic, there is a minimum in the surface layer. For δ > 0, the surface susceptibility is reduced for δ << β and enhanced for δ similar β . The curve has a maximum in the surface layer.