Fig. 1
From: Nature of the metal-insulator transition in few-unit-cell-thick LaNiO3 films
Growth and surface characterization of ultrathin LaNiO3 films. a RHEED intensity oscillation during the growth of the homoepitaxial LaAlO3 buffer layer and 0.5 to 3.5 u.c. of LaNiO3 ultrathin films with both NiO2 and LaO surface terminations. b X-ray reflectometry measurements for a 2 u.c. LaNiO3 film with LaO surface termination. c ABF STEM image of the LaNiO3/LaAlO3 interface in cross-sectional geometry with black atom contrast and drift correction applied. Scale bar, 5 nm. Also shown is the magnification of the interface area with schematic atomic structure overlay identifying both metal and oxygen sites. The LaNiO3 layers exhibited an out of plane expansion of 4 ± 0.5% as compared to the LAO substrate with no measurable in-plane expansion
