  The LaAlO3/SrTiO3 (001) thin film materials system was studied using in situ,
simultaneous x-ray diffuse scattering and specular reflectivity during pulsed
laser deposition. Using this method, we are able to measure the time dependence
of the characteristic surface length scale and the characteristic time for both
in-plane and downhill diffusion. These data allow for the determination of the
activation energy for various diffusion processes as a function of LaAlO3
thickness. Additionally, we show that the downhill diffusion rate of the first
monolayer is distinctly different than subsequent layers. These results are
directly compared to previous experimental observations seen during the
deposition of homoepitaxial SrTiO3 (001).
