Crystal Growth Prediction by First-Principles Calculations for Epitaxial Piezoelectric Thin Films

A computational prediction scheme of preferred orientations on various substrates by first principles calculation was proposed to design epitaxial piezoelectric thin film fabricated by sputtering, chemical vapor deposition and molecular beam epitaxy processes. At first, we computed epitaxial strain in piezoelectric thin film caused by lattice mismatch with substrate. When epitaxial strain is applied to crystal unit cell, total energy was evaluated by employing pseudo-potential method in density functional theory. Then, preferred orientations were predicted in view of stability of crystal cluster with various conformations on substrate. From application to BaTiO3 thin films fabricated on SrTiO3 (110), SrTiO3 (001), MgO (100) and LaTiO3 (001), calculations indicated that total energy increment of cluster was available to evaluate the possibility of crystal growth. Calculational results of preferred orientations had good correlation with experimental.