Electrostatic effects of the MnBi2Te4-superconductor hetero-structures in chiral Majorana search

TL;DR

This paper investigates how electrostatic effects influence the realization of chiral Majorana modes in MnBi2Te4-superconductor heterostructures, revealing complexities in experimental control but confirming the mode's robustness.

Contribution

It introduces a self-consistent Schrodinger-Poisson simulation to analyze electrostatic effects on topological states, advancing understanding beyond minimal models.

Findings

Electrostatic potential significantly affects the superconducting proximity effect.

The topological region is narrower than predicted by minimal models.

Chiral Majorana modes remain achievable within a broad parameter range.

Abstract

The realization of chiral Majorana modes is a challenging task. We aim to comprehend the phase diagrams and parameter control capabilities of the actual devices used in the chiral Majorana search. Beyond the well-known minimal models, we develop a numerical simulation scheme using a self-consistent Schrodinger-Poisson approach to study, as an example, the MnBi2Te4 thin film coupled to an s-wave superconductor. We show that both the superconducting proximity effect and the tunability of the chemical potential for the topological surface states are significantly influenced by the gate-induced electrostatic potential. This complicates the implementation in experiments, and the actual topological region will be narrowed in stark contrast to those predicted in the previous minimal models. Nevertheless, we demonstrate that the chiral Majorana mode still exists in a wide range of experimental parameters with practical tunability.