Majorana Zero Modes in Semiconductor Nanowires in Contact with Higher-$T_c$ Superconductors

TL;DR

This paper explores the potential for stabilizing Majorana zero modes in semiconductor nanowires coupled with high-temperature superconductors, focusing on iron pnictides and cuprates, and finds promising configurations for elevated-temperature operation.

Contribution

It introduces the concept of using higher-$T_c$ superconductors like iron pnictides and cuprates to support Majorana zero modes in nanowires, highlighting specific surface geometries for improved stability.

Findings

Majorana zero modes can be supported at higher temperatures with certain superconductor-nanowire configurations.

Step-like surfaces in orthorhombic superconductors like YBCO enhance Majorana mode stability.

Sign-changing s-wave gaps in iron pnictides influence Majorana mode realization.

Abstract

We analyze the prospects for stabilizing Majorana zero modes in semiconductor nanowires that are proximity-coupled to higher-temperature superconductors. We begin with the case of iron pnictides which, though they are s-wave superconductors, are believed to have superconducting gaps that change sign. We then consider the case of cuprate superconudctors. We show that a nanowire on a step-like surface, especially in an orthorhombic material such as YBCO, can support Majorana zero modes at an elevated temperature.