Supercurrents in Josephson junctions with chiral molecular potentials

TL;DR

This paper demonstrates how chiral molecules influence spin-polarized supercurrents in Josephson junctions, revealing chirality-dependent effects that can be harnessed for molecular detection and spintronic applications.

Contribution

It introduces a theoretical model showing how molecular chirality affects spin supercurrents in Josephson junctions, enabling chirality detection via superconducting transport.

Findings

Chiral molecules induce distinct spin supercurrents depending on enantiomeric form.

Chirality effects persist over a range of temperatures below the critical temperature.

Control of molecular orientation enhances the chirality-dependent response.

Abstract

The influence of chiral molecular potentials on phase-coherent transport in superconducting Josephson junctions is investigated. Within a Bogoliubov-de Gennes tight-binding framework, an SNS junction functionalized by adsorbed chiral molecules is modeled, where electrostatic gradients generated by the molecules induce spin-orbit coupling in the normal region. The equilibrium charge current-phase relation is found to remain largely insensitive to molecular chirality in symmetric, zero-field configurations. In contrast, the spin supercurrent exhibits a pronounced chirality-dependent response, with opposite enantiomers producing distinct and anisotropic spin-polarized Josephson currents. The resulting handedness contrast can be enhanced through control parameters such as molecular orientation and the strength of the induced spin-orbit coupling. The temperature dependence of these currents further shows that the chirality-dependent signatures persist across a range of temperatures well below the superconducting critical temperature. These results establish Josephson interferometry as a phase-sensitive and accessible platform for detecting molecular chirality and highlight spin-polarized superconducting transport as a promising route toward integrating chiral molecular functionality into superconducting spintronic devices.