<i>In Situ</i> studies of LaNiO3 growth by oxide molecular beam epitaxy

LaNiO₃ films have triggered enormous interest owing to its paramagnetic and metallic behavior [1] as well as the recent discovery of superconductivity in RNiO₃-based heterostructures. The quality of the deposited film is known to depend strongly on the structure and composition of the single crystal substrate surface. Here, exploiting in situ synchrotron X-ray investigation during thin film growth by molecular beam epitaxy, we study and understand the growth behavior of LaNiO₃ films on (LaAlO₃)(Sr₂AlTaO₆) (001) substrates with different surface compositions, in combination with resonant anomalous diffraction measurements [2]. We find that the fabrication of atomically smooth, high quality and phase pure epitaxial LaNiO₃ films can be achieved on LSAT substrates, irrespective of initial substrate surface composition and layer-by-layer deposition sequence, illustrating that dynamic rearrangement of layers occurs during the growth of complex oxides on top of mixed-terminated substrates. This has important implications regarding the use of a wider variety of substrates for fundamental studies on complex oxide systems.