Strain release at the graphene-Ni(100) interface investigated by in-situ and operando scanning tunnelling microscopy

TL;DR

This study uses in-situ scanning tunneling microscopy to explore how strain at the graphene-Ni(100) interface influences the morphology and properties of graphene during growth, revealing mechanisms of strain release and potential for nanoscale property tuning.

Contribution

It provides real-time insights into strain release mechanisms at the graphene-Ni(100) interface during growth, highlighting the role of moiré patterns and local rotation in strain management.

Findings

Strain release governs graphene morphology during growth.

Moiré patterns and local rotation facilitate strain relaxation.

Nanoscale property tuning via interface strain is possible.

Abstract

Interface strain can significantly influence the mechanical, electronic and magnetic properties of low-dimensional materials. Here we investigated by scanning tunneling microscopy how the stress introduced by a mismatched interface affects the structure of a growing graphene (Gr) layer on a Ni(100) surface in real time during the process. Strain release appears to be the main factor governing morphology, with the interplay of two simultaneous driving forces: on the one side the need to obtain two-dimensional best registry with the substrate, via formation of moir\'e patterns, on the other side the requirement of optimal one-dimensional in-plane matching with the transforming nickel carbide layer, achieved by local rotation of the growing Gr flake. Our work suggests the possibility of tuning the local properties of two-dimensional films at the nanoscale through exploitation of strain at a one-dimensional interface.