Noncollinear magnetism and half-metallicity in biased bilayer zigzag graphene nanoribbons

TL;DR

This paper investigates the magnetic properties and half-metallicity in biased bilayer zigzag graphene nanoribbons, revealing various magnetic phases and seven types of half-metallic states with potential spintronic applications.

Contribution

It introduces a classification of magnetic states based on edge polarizations and predicts seven distinct half-metallic states in biased bilayer zigzag graphene nanoribbons.

Findings

Identification of coplanar magnetic phase and its dependence on bias voltage

Prediction of seven distinct half-metallic states with quantized conductances

Analysis of edge polarization effects on magnetic and electronic properties

Abstract

We study in this paper the edge polarizations and their consequences for a biased Bernal stacked bilayer graphene nanoribbon with zigzag termination. The magnetic states are classified according to the interlayer and intralayer couplings between the edge polarizations, and the magnetic phase diagram of doping versus bias voltage is given. Coplanar magnetic phase is found and the variation of its magnetic structure with the bias voltage is investigated. For all the magnetic states, we also discuss the possibility of the half-metallicity, and for a ribbon with perfect zigzag edges we predict seven kinds of the half-metallic states, which are characterized by their distinct magnetic structures and quantized electrical conductances along the ribbon.