Laser MBE for atomic layer by layer growth of LaNiO$_{3}$ films and superlattices from separate oxide targets

Laser MBE was used to grow Nickelate thin films and superlattices in atomic layer by layer manner from separate oxide targets. Stoichiometry and full layer coverage was controlled by in-situ monitoring of Reflection High Energy Electron Diffraction (RHEED) intensity oscillation. LaNiO$_{3}$ ultra-thin films were grown from La$_{2}$O$_{3}$ and NiO targets on LaAlO$_{3}$ and SrTiO$_{3}$ substrates. X-ray diffraction, x-ray reflectivity, and atomic force microscopy were used to characterize the structure, thickness, and surface morphology of the films. The origin of thickness dependent metal to insulator transition was studied using the transport properties and x-ray absorption spectroscopy measurements. Single unit cell LaNiO$_{3}$/LaAlO$_{3}$ superlattices were grown from La$_{2}$O$_{3}$, NiO and Al$_{2}$O$_{3}$ targets on LaAlO$_{3}$ substrate. By means of polarization-dependent x-ray Absorption Spectroscopy, orbital ordering in these supperlattices was studied and the results are presented herein.