Spin-Orbit Protection of Induced Superconductivity in Majorana Nanowires

TL;DR

This study investigates how spin-orbit interaction influences the induced superconducting gap in Majorana nanowires, revealing the impact of device geometry and electrostatic gates on the spin-orbit field orientation.

Contribution

It provides a detailed analysis of spin-orbit interaction strength and direction in nanowires, using realistic simulations to enhance understanding of Majorana zero modes.

Findings

Spin-orbit interaction strength is 0.15-0.35 eV·Å.

The spin-orbit field direction is strongly affected by device geometry.

The approach identifies the spin-orbit field orientation in nanowires.

Abstract

Spin-orbit interaction (SOI) plays a key role in creating Majorana zero modes in semiconductor nanowires proximity coupled to a superconductor. We track the evolution of the induced superconducting gap in InSb nanowires coupled to a NbTiN superconductor in a large range of magnetic field strengths and orientations. Based on realistic simulations of our devices, we reveal SOI with a strength of 0.15-0.35 eV$\require{mediawiki-texvc}\AA$. Our approach identifies the direction of the spin-orbit field, which is strongly affected by the superconductor geometry and electrostatic gates.