Magnetism in amorphous carbon

TL;DR

This study uses first-principles simulations to explore how specific atomic structures in amorphous carbon contribute to its observed ferromagnetism, highlighting the role of 3-fold coordinated carbon atoms.

Contribution

It demonstrates that the presence and geometry of $sp^2$-like 3-fold coordinated carbon atoms are crucial for inducing magnetism in amorphous carbon.

Findings

3-fold coordinated carbon atoms are key to magnetism

Detailed geometries induce magnetic order

Supports experimental ferromagnetism reports

Abstract

We investigate magnetism in amorphous carbon as suggested by the recently reported ferromagnetism in a new form of amorphous carbon. We use spin constrained first-principles simulations to obtain amorphous carbon structures with the desired magnetization. We show that the existence of $sp^2$-like 3-fold coordinated carbon atoms plays an important role in obtaining magnetism in amorphous carbon. The detailed geometries of 3-fold carbon atoms induce the magnetic order in amorphous carbon.