Monovacancy-induced magnetism in graphene bilayers

Choi, Sangkook; Jeong, Byoung Wook; Kim, Seungchul; Kim, Gunn

doi:10.1088/0953-8984/20/23/235220

Cited by 30 publications

(37 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6 The calculated magnetic moment in graphene with vacancies varies broadly (1.04 1.84 µ B ), depending on the vacancy concentration. 32,[37][38][39] In case of silicene and germanene, several theoretical studies have focused on the structures, energetics and transport of vacancies. Berdiyorov and Peeters reported a significant role of vacancies in tuning the electronic structure of silicene and reducing the thermal stability of silicene.…”

Section: Introductionmentioning

confidence: 99%

Electronic and magnetic properties of graphene, silicene and germanene with varying vacancy concentration

Ali

Liu

et al. 2017

AIP Advances

View full text Add to dashboard Cite

The experimental realization of two-dimensional materials such as graphene, silicene and germanene has attracted incredible interest ranging from understanding their physical properties to device applications. During the fabrication and processing of these two-dimensional materials, structural defects such as vacancies may be produced. In this work we have systemically investigated the formation energies, electronic and magnetic properties of graphene, silicene and germanene with vacancies in the framework of spin polarized density functional theory. It is found that the magnetic moment of graphene and silicene with vacancies decreases with the increase in the concentration of vacancies. However, germanene remains non-magnetic irrespective of the vacancy concentration. Low-buckled silicene and germanene with vacancies may possess remarkable band gaps, in contrast to planar graphene with vacancies. With the formation of vacancies silicene and germanene demonstrate a transition from semimetal to semiconductor, while graphene turns to be metallic.

show abstract

Section: Introductionmentioning

confidence: 99%

Electronic and magnetic properties of graphene, silicene and germanene with varying vacancy concentration

Ali

Liu

et al. 2017

AIP Advances

View full text Add to dashboard Cite

show abstract

“…Single-atom vacancies in bulk graphene are the simplest structures complying, in principle, with the conditions for the appearance of extended π magnetic moments, both in monolayer [12][13][14][15][16]18,19,34 and multilayer graphene. [35][36][37] When H saturation of the dangling bonds (left upon removal of a C atom) prevents the Jahn-Teller reconstruction of the vacancy, the value of the induced magnetic moment is expected to be 1 μ B for the π electrons plus 0 or 1 μ B for the σ bonds, depending on whether three or two H atoms are available for saturation, respectively. Discrepancies, however, can be found in the literature regarding the actual value of the magnetic moment when a single H (or no H at all) saturates a dangling bond and the vacancy reconstructs (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Critical analysis of vacancy-induced magnetism in monolayer and bilayer graphene

2012

View full text Add to dashboard Cite

The observation of intrinsic magnetic order in graphene and graphene-based materials relies on the formation of magnetic moments and a sufficiently strong mutual interaction. Vacancies are arguably considered the primary source of magnetic moments. Here we present an in-depth density functional theory study of the spin-resolved electronic structure of (monoatomic) vacancies in graphene and bilayer graphene. We use two different methodologies: supercell calculations with the SIESTA code and cluster-embedded calculations with the ALACANT package. Our results are conclusive: The vacancy-induced extended π magnetic moments, which present long-range interactions and are capable of magnetic ordering, vanish at any experimentally relevant vacancy concentration. This holds for σ -bond passivated and unpassivated reconstructed vacancies, although, for the unpassivated ones, the disappearance of the π magnetic moments is accompanied by a very large magnetic susceptibility. Only for the unlikely case of a full σ -bond passivation, preventing the reconstruction of the vacancy, a full value of 1 μ B for the π extended magnetic moment is recovered for both monolayer and bilayer cases. Our results put on hold claims of vacancy-induced ferromagnetic or antiferromagnetic order in graphene-based systems, while still leaving the door open to σ -type paramagnetism.

show abstract

“…1 This has prompted the study of a variety of defects at different carbon atomic configurations such as graphite, 2 graphene, 3,4 nanotubes, 5,6 and other configurations, 7,8 including defect-free diamond surfaces. 9 Here, in this work, we consider the appearance of localized magnetic moments near defects on the silicon carbide (β-SiC) (110) cubic surface.…”

mentioning

confidence: 99%

Theoretical study of magnetic moments induced by defects at the SiC(110) surface

2011

View full text Add to dashboard Cite

The effect of different surface defects on the atomic and electronic structures of cubic β- SiC(110) surface are studied by means of a first-principles calculation based on density-functional theory using the SIESTA code. In the calculations, different spin populations at each atom are allowed. We find that while adsorption of atomic O, N, or H on surface C atoms do not induce magnetic moments on SiC(110), Si vacancies, substitutional C at the Si sites, and H or F adsorbed on Si surface sites induce localized magnetic moments as large as 0.7 μ B at the C atoms close to the defect. The local magnetic moment arrangement varies from ferromagnetic in the case of H adsorption to antiferromagnetic in the Si vacancy and substitutional C cases. The case of H adsorption on Si surface atoms is discussed in detail. It is concluded that magnetism is mainly owing to the local character of the C valence orbitals. Here, in this work, we consider the appearance of localized magnetic moments near defects on the silicon carbide (β-SiC) (110) cubic surface. The quasi-one-dimensional character of the Si-C chains at the surface and the localized character of the carbon atomic valence charge suggest the possibility of defect-induced magnetism. For many years now, silicon carbide has been considered as a compound with important potential practical applications such as power electronics, heterogeneous catalysis support, structural and protective components for use in future nuclear fusion reactors, etc. Recently, this interest has been fostered by the possibility to obtain SiC in different atomic configurations ranging from macromolecules such as fullerenes to two-dimensional sheets and their wrapped configuration in nanotubes (see, for instance, the work of Melinon et al. 10 and references therein).The free SiC(110) surface has been theoretically studied by Sabisch et al. 11 (for a complete review of the different SiC surfaces, see Ref. 12). Unlike other surface orientations, the free SiC(110) surface does not present any reconstruction, as different theoretical works reveal.12 To the best of our knowledge, there is no experimental study published about this surface.Here, we present the results of a first-principles calculation of different defects at the SiC(110) surface. The calculations throughout this work were performed within the densityfunctional theory (DFT), 13 using the generalized gradient approximation (GGA) 14 with partial core corrections. 20 We have found the standard double-ζ basis with polarization orbitals (DZP) satisfactory, and it has been used throughout this work. The bulk calculation yields a lattice constant of 4.41Å (Si-C bond length of 1.91Å), in fair agreement with the experimental value of 4.36Å. We find a partially ionic Si-C bond with a charge transfer of 0.45 electrons to the Si atom as evaluated using a Mulliken population analysis. We obtain a band gap of 1.31 eV, similar to the 1.29 eV band gap calculated by Sabisch et al. 11 and to be compared to the experimental one of 2.417 eV. 21To simulate th...

show abstract

Monovacancy-induced magnetism in graphene bilayers

Cited by 30 publications

References 22 publications

Electronic and magnetic properties of graphene, silicene and germanene with varying vacancy concentration

Electronic and magnetic properties of graphene, silicene and germanene with varying vacancy concentration

Critical analysis of vacancy-induced magnetism in monolayer and bilayer graphene

Theoretical study of magnetic moments induced by defects at the SiC(110) surface

Contact Info

Product

Resources

About