Probing Topological Superconductivity of oxide nanojunctions using fractional Shapiro steps

TL;DR

This paper theoretically investigates fractional Shapiro steps in oxide nanojunctions, linking their appearance to topological superconductivity and Majorana states, with potential for experimental identification of topological phases.

Contribution

It introduces a theoretical framework connecting fractional Shapiro steps with topological superconductivity in oxide interfaces with spin-orbit coupling.

Findings

Fractional Shapiro steps can indicate Majorana bound states.

Magnetic field tuning affects the fractional steps.

Provides a method to identify topological superconductivity.

Abstract

We theoretically discuss the emergence of fractional Shapiro steps in a Josephson junction created by confining a two-dimensional electron gas at an oxide interface. This phenomenon is induced by an alternating current of proper amplitude and frequency and can be tuned by a magnetic field applied perpendicular to the Rashba spin-orbit axis. The presence of fractional Shapiro steps can be associated with the creation of Majorana bound states at the boundaries of the superconducting leads. Our findings represent a route for the identification of topological superconductivity in non-centrosymmetric materials and confined systems in the presence of spin--orbit interaction, offering also new insights into recently explored frameworks.