Reconstruction-Stabilized Epitaxy of LaCoO3/SrTiO3(111) Heterostructures by Pulsed Laser Deposition

TL;DR

This paper demonstrates a method to grow high-quality LaCoO3/SrTiO3(111) heterostructures with sharp interfaces by using surface reconstruction and controlled pulsed laser deposition, enabling exploration of polar-oriented quantum phenomena.

Contribution

It introduces a reconstruction-stabilized epitaxy technique for polar [111] heterostructures, overcoming polar discontinuity challenges in complex oxides.

Findings

Reconstructed substrate surfaces enable stable epitaxy.

Interrupted growth allows lattice relaxation and sharp interfaces.

High-quality 2D growth achieved along polar orientations.

Abstract

Unlike widely explored complex oxide heterostructures grown along [001], the study of [111]-oriented heterointerfaces are very limited thus far. One of the main challenges is to overcome the polar discontinuity that hinders the epitaxy of atomically sharp interfaces. Here, by taking the LaCoO3/SrTiO3(111) as a prototype, we show that the reconstruction, which effectively compensates the surface polarity, can stabilize the epitaxy of the heterostructure with polar discontinuity. Reconstructed substrate surface is prepared, while the growth is controlled to form reconstruction on the film surface. To suppress the chemical diffusion across the interface, the growth is interrupted between each unit cell layer to allow the lattice relaxation at a lowered temperature. In this way, high quality two-dimensional growth is realized and the heterointerfaces exhibit sharpness at the atomic scale. Our work provides a path to precisely control the growth of complex oxide heterostructures along polar orientations that exhibit emergent quantum phenomena.