Symmetry-induced magnetism in fullerene monolayers

TL;DR

This paper demonstrates how controlling molecular and lattice symmetry in fullerene monolayers can induce and tune magnetism in otherwise non-magnetic carbon systems, offering a new approach to designing magnetic materials.

Contribution

It introduces a general design principle for symmetry-induced magnetism in fullerene monolayers using group theory analysis and discusses experimental feasibility.

Findings

Magnetism can be induced in pure-carbon fullerene monolayers through symmetry control.

Molecular symmetries $S_4$ and $C_3$ are key to understanding the origin of magnetism.

Crystalline symmetry enforcement can also induce magnetism in non-symmetric building blocks.

Abstract

Using molecular orbital theory, we introduce magnetism in pure-carbon, charge-neutral fullerene monolayers which are otherwise non-magnetic. By controlling either molecular or lattice symmetry, we can realise highly-tuneable magnetic fullerene monolayers. We demonstrate a general design principle based on group theory analysis and explain the origin of magnetism using two representative systems with $S_4$ and $C_3$ molecular symmetries. Moreover, for building blocks that lack appropriate molecular symmetry, we can enforce crystalline symmetry to induce magnetism as well. Finally, we discuss the experimental feasibility of realising our proposed magnetic fullerene monolayers by examining a previously synthesised C$_{60}$ system. Our work opens a new direction in introducing magnetism in non-magnetic building blocks by enforcing either molecular or lattice symmetry.