Layer Antiferromagnetic State in Bilayer Graphene : A First-Principle Investigation

TL;DR

This study uses first-principles density functional theory to confirm the stability of a layer antiferromagnetic ground state in bilayer graphene, aligning with experimental observations and including complex interactions.

Contribution

It provides a comprehensive first-principles validation of the layer antiferromagnetic state in bilayer graphene, considering remote hopping and Coulomb interactions.

Findings

Layer antiferromagnetic state is stable in bilayer graphene.

The energy gap of the LAF state is about 1.8 meV.

Surface magnetism is approximately 10^{-2} μ_B/nm^2.

Abstract

The ground state of bilayer graphene is investigated by the density functional calculations with local spin density approximation. We find a ground state with layer antiferromagnetic ordering, which has been suggested by former studies based on simplified model. The calculations prove that the layer antiferromagnetic state (LAF) is stable even if the remote hopping and nonlocal Coulomb interaction are included. The gap of the LAF state is about 1.8 meV, comparable to the experimental value. The surface magnetism in BLG is of the order of $10^{-2} \mu_B /nm^2 $.