Local Dielectric Property of Hafnium and Lanthanum Atoms in HfLaOx

In this work, we investigate the electronic contribution to local dielectric property of La2O3 and HfO2 using cluster models. The relation between the coordinate number of metal atoms and their bonding energy shows a hint that hafnia takes the cubic structure by the incorporation of La2O3 in HfO2. The local properties of polarizability and dielectric constant of La2O3 and HfO2 are closely similar to each other. It is considered to be one of the reasons why the incorporation of lanthanum atoms does not lower the permittivity of HfO2. We confirm this by the study of the local dielectric property of the HfLaOx cluster model. We compare the dielectric properties around an oxygen atom and that between the oxygen atom and a next metal atom. Our results show that the contribution to the dielectric response from the bond regions is not so large.