Voltage-induced Shapiro steps in a superconducting multi-terminal structure

TL;DR

This paper predicts that in a multi-terminal superconducting structure, voltage tuning alone can induce Shapiro-like steps in the absence of external microwave radiation, expanding understanding of Josephson effects.

Contribution

It introduces a novel mechanism for Shapiro-like steps in multi-terminal superconductors without external radiation, supported by quantitative predictions for a feasible experimental setup.

Findings

Voltage tuning induces Shapiro-like steps without external microwaves.

Predictions are made for a three-terminal superconductor-normal metal structure.

The setup can be realized experimentally.

Abstract

When a superconducting tunnel junction at a finite voltage is irradiated with microwaves, the interplay between the alternating Josephson current and the ac field gives rise to steps in the dc current known as Shapiro steps. In this work we predict that in a mesoscopic structure connected to several superconducting terminals one can induce Shapiro-like steps in the absence of any external radiation simply by tuning the voltages of the leads. To illustrate this effect we make quantitative predictions for a three-terminal structure which comprises a diffusive superconductor-normal metal-superconductor junction and a tunneling probe, a set-up which can be realized experimentally.