Dielectric constant dependence on atomic substitution of Y2BaCuO5 clarified by ab initio calculations

The improvement of the microwave properties is an important goal to increase the performance and application of communication devices. The aim of this paper is to clarify the dependence of the dielectric constant and lattice constants of the Y2BaCuO5, with space group Pbnm 62 with substitution of Zn or Ni for Cu on the C-site and Sr for Ba on the B-site and Nd or others for Y on the A-site. With ab initio calculations the density of states and the electronic band structure was calculated for different substitutions and compared to experimental data. Tracking electronic bands indicate a high dielectric constant, which is the case for the Y2BaCuO5 series, in good agreement with published experimental data. Further analysis of the electronic band structure, like band gap, and direct transition path showed the quantitative agreement to the experimental data and allows some predictions for improving the Y2BaCuO5 based microwave materials.