Hybrid-improper ferroelectric behavior in Ba3SiO/Ba3GeO oxide antiperovskite superlatticesAndrés Camilo Garcia-Castro, Jorge Hernan Quintero Quintero Orozco and Carlos José Paez GonzalezEur. Phys. J. B, 92 9 (2019) 203DOI: https://doi.org/10.1140/epjb/e2019-100175-1