First-principles calculations were used to compute the dielectric permittivities of hypothetical [La,Sc]2O3 solid solutions in the cubic (bixbyite) and hexagonal La2O3 phases. Dielectric enhancement is predicted at small Sc concentrations due to the rattling ion effect. Similar calculations for a model amorphous La2O3 struture show little change in permittivity when a small amount of Sc is substituted for La. In this case, the local environment around the Sc changes in a way that compensates for the rattling ion effect.
Citation: Applied Physics Letters
Pub Type: Journals
amorphous dielectrics, gate dielectrics, high-k dielectrics, rattling ion effect