Structural stability and electronic, magnetic properties of Ge adsorption on defected graphene: a first-principles study

In this paper, the stable configuration and the electronic and magnetic properties of Ge adsorption on defected graphene are studied by first-principles calculations. The vacancy defect induced magnetism in graphene depends upon the characteristics of covalent bonding between C atoms near the vacancy site. Substitutional boron can hole-dope graphene while nitrogen electron-dopes graphene. Therefore, the electronic properties of graphene are changed by B or N doping, turning graphene into a metal. However, substitutional B and N do not induce magnetism in graphene. On the other hand, vacancy and substitutional B defects enhance Ge adsorption on graphene, though N doping seems to have little effect on Ge adsorption. Net magnetic moments are induced in Ge-adsorbed graphene (Ge–B-doped and Ge–N-doped graphene), which is caused mainly by the p orbital electrons of Ge atom. No magnetic moment is found when Ge is adsorbed on vacancy-containing graphene.

Ge adsorption and its effect on electrical and magnetic properties of perfect and defect-containing (vacancy, B- and N-doped) graphene are studied by first-principles calculations.Figure optionsDownload as PowerPoint slideHighlights
► Bridge site is the most favorable adsorption site for Ge atom on the perfect and B (N) doped graphene.
► Vacancy defect will induce magnetism in graphene, Ge-adsorption transforms the vacancy system into non-magnetic.
► Substitutional B-doping makes graphene p-type while N impurity electron-dopes graphene.
► No magnetism is induced by boron or nitrogen substitutional dopants.
► Boron doping greatly enhances Ge adsorption, N-doping is found to have little effect on Ge adsorption.