Remote epitaxial frustration

TL;DR

This paper provides experimental and theoretical evidence for remote epitaxial frustration, revealing how competing interactions at the interface influence epitaxial growth and order in heterostructures.

Contribution

It introduces the concept of remote epitaxial frustration, supported by experimental signatures and density functional theory, advancing understanding of epitaxial mechanisms beyond traditional explanations.

Findings

Identification of a disordered interlayer at the interface

Observation of a 30-degree rotated epitaxial relationship

Theoretical explanation via remote epitaxial frustration mechanisms

Abstract

Remote epitaxy relaxes the constraints of conventional epitaxy, to enable low defect density, chemically abrupt heterostructures and exfoliation of single crystalline membranes. However, definitive evidence for a true remote mechanism remains elusive because most experiments can be explained by alternative mechanism that are macroscopically indistinguishable from true remote epitaxy. Using GdAuGe films grown on graphene/SiC (0001), we present two signatures that cannot be explained by the leading alternatives to the remote mechanism: (1) a few atomic layer thick disordered interlayer at the GdAuGe/graphene interface and (2) a $30\degree$ rotated epitaxial relationship between the GdAuGe film and the SiC substrate. Density functional theory calculations indicate these signatures arise from remote epitaxial \textit{frustration}, a competition amongst epitaxy to the remotely screened substrate, to graphene, and to the graphene-induced interfacial reconstruction. Tuning the amplitudes and periodicities of these competing potentials provides new opportunities to intentionally disrupt long-range order.