Magnetism of Edge Modified Nano Graphene

TL;DR

This study uses density functional theory to analyze how different edge modifications in nano graphene influence its magnetic properties, identifying promising modifications for magnetic material design.

Contribution

It provides a comparative analysis of various edge modifications in graphene molecules and their effects on magnetic states using first-principles calculations.

Findings

Radical carbon modification yields the most stable high-spin state.

Oxygen modification results in the lowest stable spin state due to spin cancellation.

Silicon and phosphorus modifications lead to complex geometries and spin distributions.

Abstract

In order to study a magnetic principle of carbon based materials, multiple spin state of zigzag edge modified graphene molecules are analyzed by the first principle density functional theory to select suitable modification element. Radical carbon modified C64H17 shows that the highest spin state is most stable, which arises from two up-spin's tetrahedral molecular orbital configuration at zigzag edge. In contrast, oxygen modified C59O5H17 show the lowest spin state to be most stable due to four spins cancellation at oxygen site. Boron modified C59B5H22 have no {\pi}-molecular orbit at boron site to bring stable molecular spin state to be the lowest one. Whereas, C59N5H2 have two {\pi}-electrons, where spins cancel each other to give the stable lowest spin state. Silicon modified C59Si5H27 and Phosphorus modified C59P5H22 show curved molecular geometry due to a large atom insertion at zigzag site, which also bring complex spin distribution. Radical carbon and dihydrogenated carbon modification are promising candidates for designing carbon-based magnetic materials.