Roadmap of the iron-based superconductor Majorana platform

Abstract

With a series of recent breakthroughs, iron-based superconductors (FeSC) with a topological Dirac surface state are becoming a promising material platform for hosting Majorana zero modes, which we refer to as the iron-Majorana platform. This platform uniquely combines high-T c superconductivity, a topological band structure, and electron correlations into a single material, successfully avoiding the difficulties of achieving intrinsic p-wave topological superconductors and superconductor/topological insulator heterojunction systems. The most important advantages of the iron-Majorana platform are its wide topological region and large quasiparticle gap, which provide strong topological protection for pure Majorana zero modes (MZMs). When the superconductor/topological insulator heterojunction systems, e.g., InAs/Al nanowire, have the controversies of being trivial Majorana-like states, the iron-Majorana platform, which possesses well-understood physics and clear experimental evidence of vortex MZMs, is more likely to be a true MZM. However, unlike the nanowire Majorana systems with clear theoretical proposals for braiding schemes, the iron-Majorana system has no concrete method for exchanging the vortex MZMs or constructing a topological qubit. In this article, we propose a roadmap of the future efforts required for more physical exploration and achieving the non-Abelian exchange statistics of MZMs based on the iron-Majorana platform.