Increased superconducting transition temperature of a niobium thin-film proximity-coupled to gold nanoparticles using linking organic molecules

TL;DR

This study demonstrates that chemically linking gold nanoparticles to niobium thin films via organic molecules can enhance the superconducting transition temperature, revealing a new method to modulate superconductivity.

Contribution

It introduces a novel approach of using organic linkers to increase the Tc of niobium films through nanoparticle coupling.

Findings

Tc increased by up to 10% with linker molecules

Zero-bias peaks observed in tunneling spectra

Linking molecules are essential for Tc enhancement

Abstract

The superconducting critical temperature, TC, of thin Nb films is significantly modified when gold nanoparticles (NPs) are chemically linked to the Nb film, with a consistent enhancement when using 3 nm long disilane linker molecules. The TC increases by up to 10% for certain linker length and NPs size. No change is observed when the nanoparticles are physisorbed with non-linking molecules. Electron tunneling spectra acquired on the linked NPs below TC typically exhibit zero-bias peaks. We attribute these results to a pairing mechanism coupling electrons in the Nb and the NPs, mediated by the organic linkers.