Spin-resolved ballistic transport in three-terminal Zigzag Graphene Nanoribbon Device

TL;DR

This paper explores spin-polarized ballistic transport in a three-terminal Zigzag graphene nanoribbon device, revealing spin filtering, quantum interference, and room-temperature stability, with implications for spintronic applications.

Contribution

It demonstrates spin-selective transport and half-metallic behavior in ZGNRs under Zeeman fields, highlighting quantum confinement and edge effects for spintronic device design.

Findings

Zeeman field induces spin filtering and half-metallicity.

Fabry-Pérot-like interference observed in conductance.

Spin current tunable by magnetic field and gate voltage.

Abstract

We investigate the spin-polarized ballistic transport in a three-terminal Zigzag graphene nanoribbon (ZGNR) device using a tight binding model, non-equilibrium Green function formalism within the Landauer-B\"{u}ttiker framework. We study the transmission spectrum, density of states, I-V characteristics, spin-resolved conductance and spin current by varying ribbon geometries and an out-of-plane Zeeman field. In absence of magnetization, transport is dominated by subband quantization and resonant edge states, with pronounced dependence on ribbon width and length while the introduction of a Zeeman field offers spin-selective transport and inducing half-metallic behavior, particularly in narrower ribbons, highlighting the interplay between quantum confinement, edge-localized states and spin-dependent interactions. Moreover, we found Fabry-P\'{e}rot-like interference in conductance spectrum and bias-driven mode activation with strong spin filtering effects. The spin current is found to be tunable via magnetic field and gate voltage. Also, it remains stable under thermal fluctuations, demonstrating suitability for room-temperature operation. Finally, the energy and width dependence of the Fano factor reveals distinct quantum interference features and spin-polarized transport signatures. These findings indicate the potential of the three-terminal ZGNR based device for scalable and gate-controllable spintronic applications.