Critical Josephson current through a bistable single-molecule junction

TL;DR

This paper investigates how a bistable two-level system within a single-molecule junction influences the critical Josephson current, revealing that the two-level system can significantly alter the junction's behavior and suppress -junction characteristics.

Contribution

It introduces a model combining a quantum dot with a two-level system to study their effect on Josephson current, providing new insights into molecular junction behavior.

Findings

The two-level system can significantly modify the critical current.

-junction behavior can be suppressed by the two-level system.

The model predicts substantial changes in Josephson current due to molecular bistability.

Abstract

We compute the critical Josephson current through a single-molecule junction. As a model for a molecule with a bistable conformational degree of freedom, we study an interacting single-level quantum dot coupled to a two-level system and weakly connected to two superconducting electrodes. We perform a lowest-order perturbative calculation of the critical current and show that it can significantly change due to the two-level system. In particular, the \pi-junction behavior, generally present for strong interactions, can be completely suppressed.