Spin-layer Locked Gapless States in Gated Bilayer Graphene

TL;DR

This paper reveals that in gated bilayer graphene with stacking domain walls and magnetic defects, topologically protected spin-polarized currents are localized in a single layer, offering potential for spintronic device applications.

Contribution

It demonstrates that magnetic defects lift spin degeneracy in topological states, resulting in spin-polarized currents confined to one layer in bilayer graphene.

Findings

Spin-polarized currents are localized in a single layer.

Magnetic defects perturb but do not destroy topological states.

One gapless state remains robust despite defects.

Abstract

Gated bilayer graphene exhibits spin-degenerate gapless states with a topological character localized at stacking domain walls. These states allow for one-dimensional currents along the domain walls. We herein demonstrate that these topologically protected currents are spin -polarized and locked in a single layer when bilayer graphene contains stacking domain walls decorated with magnetic defects. The magnetic defects, which we model as {\pi}-vacancies, perturb the topological states but also lift their spin degeneracy. One gapless state survives the perturbation of these defects, and its spin polarization is largely localized in one layer. The spin-polarized current in the topological state flows in a single layer, and this finding suggests the possibility of effectively exploiting these states in spintronic applications.