Meissner effect induced Majorana zero modes at small magnetic field

TL;DR

This paper proposes a method to realize Majorana zero modes at magnetic fields below 10 mT using the Meissner effect in a superconductor/topological-insulator/superconductor hybrid, significantly reducing the required magnetic field compared to previous schemes.

Contribution

It introduces a novel approach leveraging the Meissner effect to achieve MZMs at much lower magnetic fields in SC/TI/SC systems, enhancing experimental feasibility.

Findings

Magnetic field requirement reduced to below 10 mT.

Control of MZMs via phase difference tuning.

Robustness against chemical potential fluctuations.

Abstract

One fundamental difficulty in realizing Majorana zero modes (MZMs) is the required high magnetic field, which causes serious issues, e.g., shrinks the superconducting gap, reduces topological region, and weakens their robustness against disorder. In this work, we propose that the Meissner effect can bring the topological superconducting phase to a superconductor/topological-insulator/superconductor (SC/TI/SC) hybrid system. Remarkably, the required magnetic field strength ($<$10 mT) to support MZMs has been reduced by several orders of magnitude compared to that ($>$0.5 T) in the previous schemes. Tuning the phase difference between the top and bottom superconductors can control the number and position of the MZMs. In addition, we account for the electrostatic potential in the superconductor/topological-insulator (SC/TI) interface through the self-consistent Schr\"odinger-Poisson calculation, which shows the experimental accessibility of our proposal. Our proposal only needs a small magnetic eld of less than 10 mT and is robust against the chemical potential fluctuation, which makes SC/TI/SC hybrid an ideal Majorana platform.