Tunable Superconducting Phase Transition in Metal-Decorated Graphene Sheets

TL;DR

This study demonstrates a simple method to create metal-decorated graphene sheets that allow independent tuning of carrier density and disorder, revealing insights into two-dimensional superconductivity.

Contribution

The paper introduces a straightforward fabrication technique using metal dewetting to produce graphene with nanoscale tin clusters, enabling controlled studies of superconductivity at fixed disorder.

Findings

Graphene with tin clusters behaves as a homogenous dirty superconductor.

Superconducting transition can be tuned by adjusting carrier density.

Method can be extended to other quantum phases.

Abstract

Using typical experimental techniques it is difficult to separate the effects of carrier density and disorder on the superconducting transition in two dimensions. Using a simple fabrication procedure based on metal layer dewetting, we have produced graphene sheets decorated with a non-percolating network of nanoscale tin clusters. These metal clusters both efficiently dope the graphene substrate and induce long-range superconducting correlations. This allows us to study the superconducting transition at fixed disorder and variable carrier concentration. We find that despite structural inhomogeneity on mesoscopic length scales (10-100 nm), this material behaves electronically as a homogenous dirty superconductor. Our simple self-assembly method establishes graphene as an ideal tunable substrate for studying induced two-dimensional electronic systems at fixed disorder and our technique can readily be extended to other order parameters such as magnetism.