Voltage-dependent spin flip in magnetically-substituted graphene nanoribbons: Toward the realization of graphene-based spintronic devices

TL;DR

This study demonstrates voltage-controlled spin state switching in chromium-doped graphene nanoribbons, showing potential for graphene-based spintronic devices by linking magnetic state transitions to conductance changes.

Contribution

First-principles simulations reveal voltage-induced magnetic state flips in doped GNRs, advancing the design of graphene spintronic components.

Findings

Antiferromagnetic ground state flips to ferromagnetic with bias

Conductance change correlates with magnetic transition

Magnetization within graphene varies with voltage

Abstract

We examine the possibility of using graphene nanoribbons (GNRs) with directly substituted chromium atoms as spintronic device. Using density functional theory, we simulate a voltage bias across a constructed GNR in a device setup, where a magnetic dimer has been substituted into the lattice. Through this first principles approach, we calculate the electronic and magnetic properties as a function of Hubbard U, voltage, and magnetic configuration. By calculating of the total energy of each magnetic configuration, we determine that initial antiferromagnetic ground state flips to a ferromagnetic state with applied bias. Mapping this transition point to the calculated conductance for the system reveals that there is a distinct change in conductance through the GNR, which indicates the possibility of a spin valve. We also show that this corresponds to a distinct change in the induced magnetization within the graphene.