Growth simulations of pulsed laser deposition on mixed terminated oxide surfaces

Complex oxide heterostructures have attracted a lot of interest recently, while they can be prepared with atomic precision. Using Pulsed Laser Deposition (PLD), one can essentially build artificial crystal structures bottom up, for example, by the depositing heterostructures, where either A, B or both cations are periodically varied in an ABO3 crystal structure. These heterostructure consisting of alternating sheets of material, are typically grown on singly terminated substrates; TiO2 terminated SrTiO3 or ScO2 terminated DyScO3. Surfaces of the mixed variant, showing ordered areas of both AO and BO2 surface termination, are shown in literature to be templates for nanostructed PLD growth of epitaxial SrRuO3 thin film structures of several nanometers in height.
Here we study this growth mechanism, which drives the formation of the epitaxial nanostructures, by employing a kinetic Monte Carlo model. A mixed terminated substrate is simulated by locally adjusting the activation energy for diffusion. Unit cell blocks are allowed to hop on a three dimensional grid, where there hopping probability depends on the number and type of neighboring cells. SrRuO3 is known to be able to grow in a stepflow-like growth mode. Here we show that this high SrRuO3 diffusivity will lead to an enhanced sensitivity to different surface areas. Furthermore the model is used to study and tune the evolution of a variation of different kinetically derived nanostructures.