A computation methodology based on ab initio evolutionary algorithms and the spin-polarized density functional theory was developed to predict two-dimensional (2D) magnetic materials. Its application to a model system borophene reveals an unexpected rich magnetism and polymorphism. A stable borophene with nonzero thickness was an antiferromagnetic (AFM) semiconductor from first-principles calculations, which can be further turned into a half metal by finite electron doping. In this borophene, the buckling and coupling among three atomic layers are not only responsible for the magnetism, but also result in an out-of-plane negative Poissons ratios under uniaxial tension, making it the first elemental material possessing auxetic and magnetic properties simultaneously.
@article{arxiv.1902.02617,
title = {Magnetic borophenes from evolutionary search},
author = {Meng-Hong Zhu and Xiao-Ji Weng and Guoying Gao and Shuai Dong and Ling-Fang Lin and Wei-Hua Wang and Qiang Zhu and Artem R. Oganov and Xiao Dong and Yongjun Tian and Xiang-Feng Zhou and Hui-Tian Wang},
journal= {arXiv preprint arXiv:1902.02617},
year = {2019}
}