Metal–Semiconductor Behavior along the Line of Stacking Order Change in Gated Multilayer Graphene

TL;DR

This paper explores how changes in the stacking order of multilayer graphene affect its metal-semiconductor behavior when an electric field is applied.

Contribution

The study reveals how stacking domain walls and atomic-scale defects influence electronic properties and create effective energy gaps.

Findings

Metallic behavior along stacking domain walls can be restored under certain gate voltages.

A flat band appears at the Fermi energy in specific conditions.

Charge in the flat band oscillates between outer layers with small gate voltage changes.

Abstract

We investigated gated multilayer graphene with stacking order changes along the armchair direction. We consider that some layers cracked to release shear strain at the stacking domain wall. The energy cones of graphene overlap along the corresponding direction in the k-space, so the topological gapless states from different valleys also overlap. However, these states strongly interact and split due to atomic-scale defects caused by the broken layers, yielding an effective energy gap. We find that for some gate voltages, the gap states cross and the metallic behavior along the stacking domain wall can be restored. In particular cases, a flat band appears at the Fermi energy. We show that for small variations in the gate voltage, the charge occupying this band oscillates between the outer layers.

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