First-principles study of the ferroelectric properties of SrTaO2N/SrTiO3 interfaces

R. C. BASTIDAS BRICEÑO; V. I. FERNÁNDEZ; R. E. ALONSO

JOURNAL OF PHYSICS CONDENSED MATTER

IOP PUBLISHING LTD

Lugar: Londres; Año: 2020 vol. 32 p. 355003 - 355015

0953-8984

First-principles calculations based on density?functional theory in the pseudo-potential approach have been performed for the total energy, crystal structure and cell polarization for SrTaO 2 N/SrTiO 3 heterostructures. Different heterojunctions were analyzed in terms of thetermination atoms at the interface plane, and periodic or non-periodic stacking in the perpendicular direction. The calculations show that the SrTaO 2 N layer is compressed along the ab-plane, while the SrTiO 3 is elongated, thus favoring the formation of P4mm local environment on both sides of the interface, leading to net macroscopic polarization. The analysis of the local polarization as a function of the distance to the interface, for each individual unit cell was found to depend on the presence of a N or an O atom at the interface,and also on the asymmetric and not uniform c-axis deformation due to the induced strain in the ab-plane. The resulting total polarization in the periodic array was ≈ 0.54 C m −2 , which makes this type of arrangement suitable for microelectronic applications.