Effect of pseudo-cubic (111)-oriented orthorhombic substrate facets on perovskite oxide thin film synthesis

TL;DR

This study explores how different orthorhombic substrate facets influence the growth and properties of perovskite oxide thin films, revealing structural details that enable property engineering through facet selection.

Contribution

It reports the preparation of pseudo-cubic (111)-oriented orthorhombic substrates and analyzes their impact on epitaxial thin film growth and interface structure.

Findings

Orthorhombic substrates with specific facets affect thin film growth.

Differences in layer stacking are explained by oxygen octahedral tilt patterns.

Facet choice enables structural control for property tuning.

Abstract

Strain engineering with different substrate facets is promising for tuning functional properties of thin film perovskite oxides. By choice of facet, different surface symmetries and chemical bond directions for epitaxial interfaces can be tailored. Here, preparation of well-defined pseudo-cubic (111)-oriented orthorhombic substrates of DyScO3 , GdScO3 , and NdGaO3 is reported. The choice of orthorhombic facet, (011)o or (101)o , both corresponding to pseudo-cubic (111)pc , gives vicinal surfaces with single or double (111pc layer terrace step heights, respectively, impacting subsequent thin film growth. Orthorhombic LaFeO3 epitaxy on the (101)o facet reveals a distinction between alternating (111)pc layers, both during and after growth. The observed differences are explained based on the oxygen octahedral tilt pattern relative to the two orthorhombic (111)pc surfaces. This robust structural detail in the orthorhombic perovskite oxides enables utilisation of different (111)pc facets for property engineering, through polyhedral connectivity control and cation coordination at epitaxial interfaces.