We have performed density functional theory calculations of graphene decorated with carbon adatoms, which bind at the bridge site of a C--C bond. Earlier studies have shown that the C adatoms have magnetic moments and have suggested the possibility of ferromagnetism with high Curie temperature. Here we propose to use a gate voltage to fine tune the magnetic moments from zero to 1μB while changing the magnetic coupling from antiferromagnetism to ferromagnetism and again to antiferromagnetism. These results are rationalized within the Stoner and RKKY models. When the SCAN meta-GGA correction is used, the magnetic moments for zero gate voltage are reduced and the Stoner band ferromagnetism is slightly weakened in the ferromagnetic region.
@article{arxiv.1805.06044,
title = {Gate-tunable magnetism of C adatoms on graphene},
author = {J. Nokelainen and I. V. Rozhansky and B. Barbiellini and E. Lähderanta and K. Pussi},
journal= {arXiv preprint arXiv:1805.06044},
year = {2019}
}