# Growth facets of SrIrO3 Thin Films and Single Crystals

## TL;DR

This study combines DFT calculations and experimental observations to analyze the growth, surface structure, and electronic properties of SrIrO3, highlighting the influence of crystallographic orientation on topological states and growth preferences.

## Contribution

It provides new insights into the energetics and structural relaxation of SrIrO3 surfaces, and proposes methods to control thin film orientation during epitaxy.

## Key findings

- (001) and (110) surfaces have similar energies.
- Single crystals show both facet orientations.
- Interfacial energy influences growth direction.

## Abstract

The crystallographic orientation of SrIrO3 surfaces is decisive for the occurrence of topological surface states. We show from DFT computations that (001) and (110) free surfaces have comparable energies, and, correspondingly, we experimentally observe that single micro-crystals exhibit both facet orientations. These surfaces are found to relax over typically the length of one oxygen octahedron, defining a structural critical thickness for thin films. A reconstruction of the electronic density associated to tilts of the oxygen octahedra is observed. On the other hand, thin films have invariably been reported to grow along the (110) direction. We show that the interfacial energy associated to the oxygen octahedra distortion for epitaxy is likely at the origin of this specific feature, and propose leads to induce (001) SrIrO3 growth.