Layer-by-layer growth by pulsed laser deposition in the unit-cell limit.

Unlike conventional growth of complex oxide heterostructures, the ultimate unit cell limit imposes strict constrains for a multitude of parameters critical to layer-by-layer growth. Here we report on detailed analysis of far-from-equilibrium growth by interrupted pulsed laser deposition with application to RENiO$_{3}$/LaAlO$_{3 }$superlattices grown on a diverse set of substrates SrTiO$_{3}$, NdGaO$_{3}$, LSAT and LaAlO$_{3}$. A combination of \textit{in-situ} high-pressure RHEED and AFM along with extensive data obtained from synchrotron based XRD and resonant XAS allows us critically assess the meaning of RHEED intensity oscillation and the effect of a polar/non-polar interface on the heteroepitaxial growth. The role of defects formed during the initial stages of growth is also addressed.