文章基本信息

标题：Robust ferromagnetism in hydrogenated graphene mediated by spin-polarized pseudospin
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作者：Hyunyoung Kim ; Junhyeok Bang ; Joongoo Kang 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：13940
DOI：10.1038/s41598-018-31934-0
语种：English
出版社：Springer Nature
摘要：The origin of the ferromagnetism in metal-free graphitic materials has been a decade-old puzzle. The possibility of long-range magnetic order in graphene has been recently questioned by the experimental findings that point defects in graphene, such as fluorine adatoms and vacancies, lead to defect-induced paramagnetism but no magnetic ordering down to 2 K. It remains controversial whether collective magnetic order in graphene can emerge from point defects at finite temperatures. This work provides a new framework for understanding the ferromagnetism in hydrogenated graphene, highlighting the key contribution of the spin-polarized pseudospin as a “mediator” of long-range magnetic interactions in graphene. Using first-principles calculations of hydrogenated graphene, we found that the unique ‘zero-energy’ position of H-induced quasilocalized states enables notable spin polarization of the graphene’s sublattice pseudospin. The pseudospin-mediated magnetic interactions between the H-induced magnetic moments stabilize the two-dimensional ferromagnetic ordering with Curie temperatures of T_c = n_H × 34,000 K for the atom percentage n_H of H adatoms. These findings show that atomic-scale control of hydrogen adsorption on graphene can give rise to a robust magnetic order.