Segregation growth and self-organization of ordered S atomic superlattices confined at interface between graphene and substrates

TL;DR

This study demonstrates the controlled growth and self-organization of ordered sulfur atomic superlattices at the graphene-S interface, enabling new electronic states in graphene with potential technological applications.

Contribution

It introduces a method to fabricate stable, well-ordered sulfur superlattices at the atomic scale on graphene interfaces, advancing atomic-scale superlattice engineering.

Findings

Successfully created stable sulfur superlattices at the interface.

Induced Kekulé distortion in graphene via superlattice period control.

Superlattices remain stable after high-temperature annealing.

Abstract

Ordered atomic-scale superlattices on surface hold great interest both for basic science and for potential applications in advanced technology. However, controlled fabrication of superlattices down to atomic scale has proven exceptionally challenging. Here we demonstrate the segregation-growth and self-organization of ordered S atomic superlattices confined at the interface between graphene and S-rich Cu substrates. Scanning tunneling microscope (STM) studies show that, by finely controlling the growth temperature, we obtain well-ordered S (sub)nanometer-cluster superlattice and monoatomic superlattices with various periods at the interface. These atomic superlattices are stable in atmospheric environment and robust even after high-temperature annealing (~ 350 oC). Our experiments demonstrate that the S monoatomic superlattice can drive graphene into the electronic Kekul\'e distortion phase when the period of the ordered S adatoms is commensurate with graphene lattice. Our results not only open a road to realize atomic-scale superlattices at interfaces, but also provide a new route to realize exotic electronic states in graphene.