Probing the chirality of 1D Majorana edge states around a 2D nanoflake in a superconductor

TL;DR

This paper investigates the properties of Majorana edge states around a 2D nanoflake in a superconductor, focusing on their chirality, spatial extent, and how to experimentally detect them using scanning tunneling spectroscopy.

Contribution

It provides a detailed analysis of the topological phase diagram and proposes a practical method to probe Majorana edge state chirality with a double tip setup.

Findings

Majorana edge states exhibit specific chirality around the nanoflake.

Tuning the chemical potential affects the topological phase separation.

Scanning tunneling spectroscopy can effectively probe Majorana edge state chirality.

Abstract

The interplay between superconductivity, magnetic field and spin-orbit coupling can lead to the realization of non--trivial topological phases. Recent experiments have found signatures of such phases in magnetic nanoflakes formed by nanostructures coupled to a superconducting substrate. These heterostructures comprise a topologically non-trivial region surrounded by a trivial one due to the finite magnetic exchange field induced by the magnetic nanoflake. The analysis of the topological phase diagram of such a system shows that a similar phase separation occurs by tuning the chemical potential of the nanoflake. In this paper, we study such a possibility in detail, analyzing the spatial extent of the edge modes circulating around the nanoflake and discussing some practical implementations. We also show how the chirality of Majorana edge states can be probed using scanning tunneling spectroscopy with a double tip setup.