Spin-Polarized Majorana Zero Modes in Proximitized Superconducting Penta-Silicene Nanoribbons

TL;DR

This paper theoretically demonstrates the emergence of spin-polarized Majorana zero modes in proximitized penta-silicene nanoribbons with induced p-wave superconductivity, magnetic field, and Rashba spin-orbit coupling, indicating potential for quantum computing applications.

Contribution

It introduces a model showing how spin-polarized Majorana zero modes can be realized in penta-silicene nanoribbons with induced p-wave pairing, magnetic field, and spin-orbit coupling.

Findings

Observation of topological phase transition via gap closing and reopening.

Existence of zero-energy states with spin polarization at nanoribbon ends.

Potential for silicene-based Majorana devices with multiple MZMs.

Abstract

We theoretically investigate the possibility of obtaining Majorana zero modes (MZMs) in penta-silicene nanoribbons (p-SiNRs) with induced \textit{p}-wave superconductivity. The model explicitly considers an external magnetic field perpendicularly applied to the nanoribbon plane, as well as an extrinsic Rashba spin-orbit coupling (RSOC), in addition to the first nearest neighbor hopping term and \textit{p}-wave superconducting pairing. By analyzing the dispersion relation profiles, we observe the successive closing and reopening of the induced superconducting gap with a single spin component, indicating a spin-polarized topological phase transition (TPT). Correspondingly, the plots of the energy spectrum versus the chemical potential reveal the existence of zero-energy states with a preferential spin orientation characterized by nonoverlapping wave functions localized at opposite ends of the superconducting p-SiNRs. These findings strongly suggest the emergence of topologically protected, spin-polarized MZMs at the ends of the p-SiNRs with induced \textit{p}-wave superconducting pairing, which can be realized by proximitizing the nanoribbon with an \textit{s}-wave superconductor, such as lead. The proposal paves the way for silicene-based Majorana devices hosting multiple MZMs with a well-defined spin orientation, with possible applications in fault-tolerant quantum computing platforms and Majorana spintronics.