Computational Experiments Meet Real Experiments: Finding the Right Answer Through Cross-Validation

Recent advances in nanomaterial synthesis allow for the growth of near perfect-layered materials giving rise to a novel way to combine desirable properties from different materials and even possibly enhance their properties when grown together. Superlattices, which are a periodic layering of materials, are particularly useful in state of the art memory and energy storage devices. Our study focuses on ferroelectric lead titanate (PbTiO3 ) based superlattices. We use first principles density functional theory to explain the origin of a phenomenon that occurs ubiquitously in experiments, and that, to date, was not understood. This was, the existence of a preferred polarization state leading to an experimentally measured bias, which prevents the fabrication of ideal electronics. These results could only be obtained through an interactive journey that involved performing increasingly complex simulations and increasingly cleaner and reproducible experiments.