Hybrid-improper ferroelectric behavior in Ba3SiO/Ba3GeO oxide antiperovskite superlattices

Here, we present a theoretical study of the hybrid-improper ferroelectric (HIF) behavior at the [001] (Ba 3 SiO) 1 /(Ba 3 GeO) 1 superlattices. Then, by means of first-principles calculations, we have investigated the structural and vibrational modes that allows the existence of the trilinear coupling phenomenon in this antiperovskite oxide heterostructure. The latter coupling, leading to a ferroelectric character in this system. Finally, we show the xy biaxial strain influence into the structure and the ferroelectricity, achieving an enhancement of the spontaneous polarization through this control parameter. Graphical abstract