Proximity Effect through Chiral Molecules in Nb–Graphene-Based Devices

Molecular electronics focuses on the application of molecular building blocks for the fabrication of nanoscale electronic devices. The molecules offer nanosized repeatable structures that are critical for electronic components. In this work, a monolayer of chiral molecules is used to mediate the proximity effect between Nb, which is a conventional superconductor, and graphene. The conductance spectra of an Nb/chiral-molecule monolayer/graphene device exhibit split peaks terminated by side dips at temperatures well below the critical temperature of Nb. Such features cannot be accounted for by conventional superconductivity but are compatible with the emergence of an anisotropic chiral p-wave triplet state. This scenario gains support by fitting the spectra to a corresponding theoretical model and by a unique dependence of the peak height on the direction of an applied magnetic field. In general, these results provide clear evidence for a proximity effect through organic molecules, particularly with chiral molecules that are known to support spin-selective transport. As a result, the presented device architecture may be useful in both electronic and spintronic circuits.