Exchange interactions and frustrated magnetism in single-side hydrogenated and fluorinated graphene

TL;DR

This study investigates the magnetic properties of single-side hydrogenated and fluorinated graphene, revealing frustrated ground states and potential spin-liquid behavior due to exchange interactions modeled by first-principles calculations.

Contribution

It provides the first detailed analysis of exchange interactions in C$_2$H and C$_2$F graphene, predicting frustrated magnetism and possible spin-liquid states.

Findings

Both systems exhibit frustrated ground states.

Collinear spin structures are unstable.

Potential for spin-liquid behavior at low temperatures.

Abstract

Magnetism in single-side hydrogenated (C$_2$H) and fluorinated (C$_2$F) graphene is analyzed in terms of the Heisenberg model with parameters determined from first principles. We predict a frustrated ground state for both systems, which means the instability of collinear spin structures and sheds light on the absence of a conventional magnetic ordering in defective graphene demonstrated in recent experiments. Moreover, our findings suggest a highly correlated magnetic behavior at low temperatures offering the possibility of a spin-liquid state.