Thermodynamic properties of compositionally modulated (Ba,Sr)TiO3 superlattices

The spontaneous polarization and dielectric tunability of compositionally modulated n[Ba1−x1Srx1TiO3]/m[Ba1−x2Srx2TiO3] superlattices are investigated by using a modified transverse Ising model combining with two-peak probability distribution function. The spontaneous polarization can be enhanced with both the decrease of Sr composition concentration and the increase of interfacial coupling strength. In addition, a high dielectric tunability can be achieved by adjusting the compositional concentration, the layer numbers of two alternative materials in one unit cell and the temperature.