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arXiv · 1912.10791

First-Principles Study of the Ferroelectric Properties of SrTaO$_2$N/SrTiO$_3$ Interfaces

Ruby C. Bastidas Briceño·Victoria I. Fernández·Eitel Peltzer y Blancá·Roberto E. Alonso
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Abstract

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 the termination 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 $ \approx 0.54$ C/m$^2$, which makes this type of arrangement suitable for microelectronic applications.

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Ruby C. Bastidas Briceño, Victoria I. Fernández, Eitel Peltzer y Blancá, Roberto E. Alonso. 2019-12-23. First-Principles Study of the Ferroelectric Properties of SrTaO$_2$N/SrTiO$_3$ Interfaces. https://arxiv.org/abs/1912.10791

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