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] (Ba3SiO)(1)/(Ba3GeO)(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.