A new article by NCCR MARVEL scientists published in Physical Review B presents a new computational framework to simulate the behavior of tetragonal barium titanate (BTO), a ferroelectric perovskite that can be used as an alternative to silicon in photonic integrated circuits, that use photons instead of electrons to encode and transmit information. The core of the study is the modelling of the Pockels effect, a change in the refractive index of the material in the presence of an electric field that can be used to encode information. The authors, from Mathieu Luisier’s lab at ETH Zurich and Nicola Marzari’s group at EPFL, devised a computational framework that is independent of specific functionals and relies only on standard Density Functional Theory. The results were validated by comparing them to existing experimental results, and to previous calculations based on other computational methods.