Interface energies of (100)_{YSZ} and (111)_{YSZ} epitaxial islands on (0001)_{alpha-Al_2O_3} substrates from first principles

TL;DR

This study uses first-principles calculations to compare the interface energies of different YSZ epitaxial orientations on alpha-Al2O3 substrates, revealing that the (111) orientation has a lower interface energy.

Contribution

It provides the first ab initio comparison of interface energies for (100) and (111) YSZ on alpha-Al2O3, aiding understanding of thin film islanding behavior.

Findings

(111) YSZ || (0001) alpha-Al2O3 has lower interface energy than (100) orientation.

Results help explain YSZ thin film islanding on alpha-Al2O3 substrates.

First-principles approach clarifies interface energetics relevant for thin film growth.

Abstract

We present an ab initio study of the interface energies of cubic yttria-stabilized zirconia (YSZ) epitaxial layers on a (0001)_{alpha-Al_2O_3} substrate. The interfaces are modelled using a supercell geometry and the calculations are carried out in the framework of density-functional theory (DFT) and the local-density approximation (LDA) using the projector-augmented-wave (PAW) pseudopotential approach. Our calculations clearly demonstrate that the (111)_{YSZ} || (0001)_{alpha-Al_2O_3} interface energy is lower than that of (100)_{YSZ} || (0001)_{alpha-Al_2O_3}. This result is central to understanding the behaviour of YSZ thin solid film islanding on (0001)_{alpha-Al_2O_3} substrates, either flat or in presence of defects.