Local polarization and valence distribution in LaNiO3/LaMnO3 heterostructures

TL;DR

This study investigates local polarization and valence distributions at LaNiO3/LaMnO3 heterointerfaces using advanced X-ray diffraction techniques, revealing specific valence states and electric field directions in bilayer structures.

Contribution

It introduces a Bayesian inference method to simultaneously measure local polarization and valence distributions at oxide heterointerfaces.

Findings

Mn valences are approximately +3.12 and +3.19 in the two samples.

Local electric field magnitude is about 1 GV/m.

Electric field points from LaMnO3 to LaNiO3.

Abstract

The inside of the electrical double layer at perovskite oxide heterointerfaces is examined. Here, we report the local polarization and valence distribution in LaNiO$_3$/LaMnO$_3$ and LaMnO$_3$/LaNiO$_3$ bilayers on a SrTiO$_3$ (001) substrate. Simultaneous measurements of two aspects of the structure are realized by using Bayesian inference based on resonant- and nonresonant-surface X-ray diffraction data. The results show that the average Mn valences are Mn$^{3.12+}$ and Mn$^{3.19+}$ for the two samples. The intensity of their local electric field is $\sim$1~GV/m and the direction of the field points from LaMnO$_3$ to LaNiO$_3$.