Controllable magnetic correlation between two impurities by spin-orbit coupling in graphene

TL;DR

This study demonstrates how spin-orbit coupling and chemical potential can control magnetic interactions between impurities in graphene, enabling potential device applications through tunable magnetic states.

Contribution

The paper reveals a method to switch magnetic interactions from ferromagnetic to antiferromagnetic in graphene using spin-orbit coupling and chemical potential, with implications for spintronic devices.

Findings

Spin-orbit coupling and chemical potential can induce magnetic phase transitions.

Spatial distribution symmetry is broken, causing anisotropic spin exchange.

Experimental tunability of parameters makes device applications feasible.

Abstract

Two magnetic impurities on the edge of a zigzag graphene nanoribbon strongly interact with each other via indirect coupling, which can be mediated by conducting carriers. By means of Quantum Monte Carlo (QMC) simulations, we find that the spin-orbit coupling $\lambda$ and the chemical potential $\mu$ in system can be used to drive the transition of local-spin exchange from ferromagnetism to anti-ferromagnetism. Since the tunable ranges for $\lambda$ and $\mu$ in graphene are experimentally reachable, we thus open the possibilities for its device application. The symmetry in spatial distribution is broken by the vertical and the transversal spin-spin correlations due to the effect of spin-orbit coupling, leading to the spatial anisotropy of spin exchange, which distinguish our findings from the case in normal Fermi liquid.