Anomalous Proximity Effect of Planer Topological Josephson Junctions

TL;DR

This paper investigates the anomalous proximity effect in topological Josephson junctions, revealing how Majorana bound states influence low-energy transport and proposing an experiment to observe these phenomena.

Contribution

It provides a theoretical description of the anomalous proximity effect in superconductor/semiconductor hybrids with a normal-metal segment, highlighting the role of Majorana states and odd-frequency pairs.

Findings

Quantization of zero-bias conductance in topologically nontrivial phase

Majorana bound states penetrate into the normal-metal segment

Proposed experimental setup to observe the effect

Abstract

The anomalous proximity effect in dirty superconducting junctions is one of most striking phenomena highlighting the profound nature of Majorana bound states and odd-frequency Cooper pairs in topological superconductors. Motivated by the recent experimental realization of planar topological Josephson junctions, we describe the anomalous proximity effect in a superconductor/semiconductor hybrid, where an additional dirty normal-metal segment is extended from a topological Josephson junction. The topological phase transition in the topological Josephson junction is accompanied by a drastic change in the low-energy transport properties of the attached dirty normal-metal. The quantization of the zero-bias differential conductance, which appears only in the topologically nontrivial phase, is caused by the penetration of the Majorana bound states and odd-frequency Cooper pairs into a dirty normal-metal segment. As a consequence, we propose a practical experiment for observing the anomalous proximity effect.