Interface structure, band alignment and built-in potentials at LaFeO$_3$/$\textit{n}$-SrTiO$_3$ heterojunctions

TL;DR

This study investigates how interface polarity affects band alignment and potentials in LaFeO3/n-SrTiO3 heterojunctions, revealing similar band offsets but polarity-dependent potential gradients that influence charge diffusion.

Contribution

It demonstrates that opposite interface polarities produce similar band offsets but different potential gradients, impacting charge behavior in oxide heterostructures.

Findings

Similar band offsets for opposite polarities

Polarity-dependent potential gradients in SrTiO3

Potential for hole diffusion into LaFeO3

Abstract

Interface structure at polar/non-polar interfaces has been shown to be a key factor in controlling emergent behavior in oxide heterostructures, including the LaFeO$_3$/$\textit{n}$-SrTiO$_3$ system. We demonstrate via high energy resolution x-ray photoemission that epitaxial LaFeO$_3$/$\textit{n}$-SrTiO$_3$ (001) heterojunctions engineered to have opposite interface polarities exhibit very similar band offsets and potential gradients within the LaFeO$_3$ films. However, differences in the potential gradient within the SrTiO$_3$ layer depending on polarity may promote hole diffusion into LaFeO$_3$ for applications in photocatalysis.