Engineered platforms for topological superconductivity and Majorana zero modes

TL;DR

This paper reviews the development of engineered platforms for realizing topological superconductivity and Majorana zero modes, emphasizing the physical principles, material systems, progress, and remaining challenges in creating topologically protected qubits.

Contribution

It provides a comprehensive overview of the physical principles, material systems, and current progress in engineering platforms for Majorana-based topological qubits.

Findings

Evidence of Majorana zero modes in candidate materials

Progress in material engineering for topological superconductivity

Identification of key challenges in experimental realization

Abstract

Among the major approaches that are being pursued for realizing quantum bits, the Majorana-based platform has been the most recent to be launched. It attempts to realize qubits which store quantum information in a topologically-protected manner. The quantum information is protected by its nonlocal storage in localized and well-separated Majorana zero modes, and manipulated by exploiting their nonabelian quantum exchange properties. Realizing these topological qubits is experimentally challenging, requiring superconductivity, helical electrons (created by spin-orbit coupling) and breaking of time reversal symmetry to all cooperate in an uncomfortable alliance. Over the past decade, several candidate material systems for realizing Majorana-based topological qubits have been explored, and there is accumulating, though still debated, evidence that zero modes are indeed being realized. This paper reviews the basic physical principles on which these approaches are based, the material systems that are being developed, and the current state of the field. We highlight both the progress made and the challenges that still need to be overcome.