Optimizing spin-orbit splittings in InSb Majorana nanowires

TL;DR

This paper develops a highly accurate microscopic model for InSb nanostructures to better understand and optimize spin-orbit interactions crucial for Majorana-based quantum computing.

Contribution

It introduces a symmetrized tight-binding model derived from ab initio calculations to accurately predict spin-orbit splittings in InSb nanostructures.

Findings

Accurate prediction of Dresselhaus and Rashba spin-orbit splittings.

Dependence of spin-orbit effects on growth parameters and electric fields.

Enables reliable simulations for designing topological quantum devices.

Abstract

Semiconductor-superconductor heterostructures represent a promising platform for the detection of Majorana zero modes and subsequently the processing of quantum information using their exotic non-Abelian statistics. Theoretical modeling of such low-dimensional semiconductors is generally based on phenomenological effective models. However, a more microscopic understanding of their band structure and, especially, of the spin-orbit coupling of electrons in these devices is important for optimizing their parameters for applications in quantum computing. In this paper, we approach this problem by first obtaining a highly accurate effective tight-binding model from ab initio calculations in the bulk. This model is symmetrized and correctly reproduces both the band structure and the wavefunction character. It is then used to determine Dresselhaus and Rashba spin-orbit splittings induced by finite size effects and external electric field in zincblende InSb one- and two-dimensional nanostructures as a function of growth parameters. The method presented here enables reliable simulations of realistic devices, including those used to realize exotic topological states.