Electro-thermal and mechanical simulations of laser annealing perovskite films

Conventional thermal annealing of oxide thin films (>600 °C) often induces interfacial diffusion and substrate degradation, compromising structural integrity. Nanosecond pulsed laser annealing (ns-PLA) circumvents these limitations by enabling ultrafast, localized energy deposition with minimal thermal load. However, the fundamental mechanisms governing film–substrate interactions under ns-PLA remain unclear due to the complex interplay of electromagnetic, thermal, and mechanical processes, including light–matter interactions, transient heat transfer, and stress–strain dynamics from differential thermal expansion. To address this, we present a fully coupled electro-thermo-mechanical finite element model of ns-PLA. Our model integrates Maxwell's equations in the frequency domain, transient heat transfer, and thermoelastic stress analysis. For a 3 ns, 40 mJ cm−2 pulse, simulations reveal that electromagnetic interference localizes absorption near the LaNiO3/SrTiO3 interface, deviating from Beer–Lambert predictions. Peak temperatures exceed 1100 °C, with vertical thermal gradients of ∼109 K m−1, accelerating diffusion and epitaxial ordering by three orders of magnitude compared to furnace annealing. The thermoelastic response generates transient stresses of several gigapascals, exhibiting a distinct tensile–compressive distribution across the interface. Our findings emphasize the necessity of multiphysics coupling for accurately describing ns-PLA and provide quantitative insights into stress generation during epitaxial crystallization. This work advances the understanding of non-equilibrium phenomena in oxide heterostructures and establishes ns-PLA as a versatile tool for probing and controlling such processes at the nanoscale.