Unconventional superconductivity induced in Nb films by adsorbed chiral molecules

TL;DR

This study shows that adsorbing chiral molecules on Nb superconducting films induces unconventional triplet-pairing components, evidenced by zero-bias conductance peaks, potentially enabling new superconducting spintronics devices.

Contribution

It demonstrates that chiral molecule adsorption can alter the superconducting pairing symmetry in Nb, revealing a novel method to induce unconventional superconductivity.

Findings

Zero-bias conductance peaks observed in tunneling spectra.

Indication of triplet-pairing components with d-wave or p-wave symmetry.

Chiral molecules influence the superconducting order parameter.

Abstract

Motivated by recent observations of chiral-induced magnetization and spin-selective transport we studied the effect of chiral molecules on conventional BCS superconductors. By applying scanning tunneling spectroscopy, we demonstrate that the singlet-pairing s-wave order parameter of Nb is significantly altered upon adsorption of chiral polyalanine alpha-helix molecules on its surface. The tunneling spectra exhibit zero-bias conductance peaks embedded inside gaps or gap-like features, suggesting the emergence of unconventional triplet-pairing components with either d-wave or p-wave symmetry, as corroborated by simulations. These results may open a way for realizing simple superconducting spintroinics devices.