Spin-orbital polarization of Majorana edge states in oxides nanowires

TL;DR

This paper explores how spin-orbital interactions influence Majorana edge states in oxide nanowires, revealing orbital-dependent polarization effects that are crucial for experimental detection of topological superconductivity.

Contribution

It demonstrates the impact of spin-orbital interplay on the topological phase diagram and Majorana states, highlighting orbital-dependent polarization and novel detection signatures.

Findings

Spin-orbital polarization aligns with the Zeeman field direction.

Orbital dependence causes misalignment of spin and orbital moments.

Variation in parameters affects the polarization evolution.

Abstract

We investigate a paradigmatic case of topological superconductivity in a one-dimensional nanowire with $d-$orbitals and a strong interplay of spin-orbital degrees of freedom due to the competition of orbital Rashba interaction, atomic spin-orbit coupling, and structural distortions. We demonstrate that the resulting electronic structure exhibits an orbital dependent magnetic anisotropy which affects the topological phase diagram and the character of the Majorana bound states (MBSs). The inspection of the electronic component of the MBSs reveals that the spin-orbital polarization generally occurs along the direction of the applied Zeeeman magnetic field, and transverse to the magnetic and orbital Rashba fields. The competition of symmetric and antisymmetric spin-orbit coupling remarkably leads to a misalignment of the spin and orbital moments transverse to the orbital Rashba fields, whose manifestation is essentially orbital dependent. The behavior of the spin-orbital polarization along the applied Zeeman field reflects the presence of multiple Fermi points with inequivalent orbital character in the normal state. Additionally, the response to variation of the electronic parameters related with the degree of spin-orbital entanglement leads to distinctive evolution of the spin-orbital polarization of the MBSs. These findings unveil novel paths to single-out hallmarks relevant for the experimental detection of MBSs.