Submonolayer growth of BaTiO3 thin film via pulsed laser deposition: A kinetic Monte Carlo simulation

Distinguishing with the traditional solid-on-solid model, the adatom bonding is specially considered to describe the atom combined according to the perovskite structure, and the pulsed laser deposition growth of the perovskite thin film on the surface of square lattice substrate of homoepitaxial system is considered as three stochastic incidents such as the deposition, diffusion, and bonding of adatoms. We proposed an energy-dependent kinetic Monte Carlo approach to simulate BaTiO3 thin film growth via pulsed laser deposition within the submonolayer regime, in which the coverage theta is less than 1. In the simulation, first- and second-nearest-neighbor interactions are taken into account by the Born-Mayer-Huggins potential. Varying the values of the laser repetition rate and pulse duration, the relative curves of the island density and island size versus coverage were obtained. The simulation results show that the island density increases, while the island size decreases with the pulse frequency. When the pulse repetition rate is less than 1 kHz, there is no obvious variation for the curves of the island density and island size versus coverage. However, when the pulse repetition rate is larger than 1 kHz, the island density does not change for theta < 0.1, and with the pulse duration, the island density increases while the island size decreases for theta>0.1. They are in good agreement with the previous experimental observations. It provides an understanding of the evolution of the morphology of the BaTiO3 thin film in submonolayer growth and a basic exploration of the epitaxial growth process of ionic oxides with perovskite-type structures.