First-principles calculation of the band offset at BaO/BaTiO$_3$ and SrO/SrTiO$_3$ interfaces

TL;DR

This study uses first-principles calculations to analyze the atomic structures and electronic properties of BaO/BaTiO$_3$ and SrO/SrTiO$_3$ interfaces, focusing on band offsets and their tunability under strain for potential electronic applications.

Contribution

It provides detailed first-principles insights into the band offsets and interface characteristics of BaO/BaTiO$_3$ and SrO/SrTiO$_3$ heterojunctions, including their strain-dependent tunability.

Findings

No electronic interface states detected at junctions.

Perovskite character dominates at the interface layer.

Band offset tunability with substrate-induced strain.

Abstract

We report first-principles density-functional pseudopotential calculations on the atomic structures, electronic properties, and band offsets of BaO/BaTiO$_3$ and SrO/SrTiO$_3$ nanosized heterojunctions grown on top of a silicon substrate. The density of states at the junction does not reveal any electronic induced interface states. A dominant perovskite character is found at the interface layer. The tunability of the band offset with the strain conditions imposed by the substrate is studied. Using previously reported theoretical data available for Si/SrO, Si/BaO and BaTiO$_{3}$/SrRuO$_{3}$ interfaces we extrapolate a value for the band alignments along the whole gate stacks of technological interest: Si/SrO/SrTiO$_3$ and Si/BaO/BaTiO$_3$/SrRuO$_3$ heterostructures.