Structure and magnetic properties of adatoms on carbon nanotubes

Lehtinen, Pekka; Foster, Adam S.; Ayuela, Andrés; Vehviläinen, Timo; Nieminen, Risto M.

doi:10.1103/physrevb.69.155422

Cited by 94 publications

(56 citation statements)

References 34 publications

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“…While the origin of magnetic ordering in such systems is yet to be fully understood, it has been suggested that spin polarization may arise from local structural defects, 33,36,41,53 sterically protected carbon radicals 34 and chemical impurities. 30,40,43 A unique mechanism for spin ordering in graphene based systems is related to the appearance of edge states. [18][19][20][21][22][23][24][25][26][27][28][29]42,[45][46][47][48][49][50][51][52] When cutting a graphene sheet along its zigzag axis to form a narrow and elongated graphene nanoribbon (GNR), distinct electronic states appear, which are localized around the exposed edges.…”

Section: Introductionmentioning

confidence: 99%

Half-Metallic Zigzag Carbon Nanotube Dots

Hod

Scuseria

2008

ACS Nano

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A comprehensive first-principles theoretical study of the electronic properties and half-metallic nature of finite zigzag carbon nanotubes is presented. Unlike previous reports, we find that all nanotubes studied present a spin-polarized ground state, where opposite spins are localized at the two zigzag edges in a long-range antifferomagnetic configuration. Relative stability analysis of the different spin states indicate that, for the shorter segments, spin-ordering should be present even at room temperature. The energy gap between the highest occupied and the lowest unoccupied molecular orbitals of the finite systems is found to be inversely proportional to the nanotubes segments length, suggesting a route to control their electronic properties. Similar to the case of zigzag graphene nanoribbons, half-metallic behavior is obtained under the influence of an external axial electric field.

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Section: Introductionmentioning

confidence: 99%

Half-Metallic Zigzag Carbon Nanotube Dots

Hod

Scuseria

2008

ACS Nano

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“…Earlier simulations showed that CA and some other defects in nanotubes and other carbon nanomaterials 95,96 can have local magnetic moments. Although the standard STM with the tip made from a nonmagnetic material probes simultaneously the LDOS corresponding to majority and minority spins, an account for magnetism can change the positions of defect-induced peaks.…”

Section: G Spin-polarized Calculationsmentioning

confidence: 99%

Modifying the electronic structure of semiconducting single-walled carbon nanotubes byAr+ion irradiation

et al. 2009

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Local controllable modification of the electronic structure of carbon nanomaterials is important for the development of carbon-based nanoelectronics. By combining density-functional theory simulations with Arion-irradiation experiments and low-temperature scanning tunneling microscopy and spectroscopy ͑STM/STS͒ characterization of the irradiated samples, we study the changes in the electronic structure of single-walled carbon nanotubes due to the impacts of energetic ions. As nearly all irradiation-induced defects look as nondistinctive hillocklike features in the STM images, we compare the experimentally measured STS spectra to the computed local density of states of the most typical defects with an aim to identify the type of defects and assess their abundance and effects on the local electronic structure. We show that individual irradiationinduced defects can give rise to single and multiple peaks in the band gap of the semiconducting nanotubes and that a similar effect can be achieved when several defects are close to each other. We further study the stability of defects and their evolution during STM measurements. Our results not only shed light on the abundance of the irradiation-induced defects in carbon nanotubes and their signatures in STS spectra but also suggest a way the STM can be used for engineering the local electronic structure of defected carbon nanotubes.

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“…[24][25][26] They predicted that carbon atoms adsorbed to ͑n ϫ n͒ supercell for n = 5, 6 and 7 generates a magnetic moment of ϳ0.5 B . However, our study for n =2-9 demonstrates that the magnetic moment as well as P vary with n up to n = 9.…”

Section: B Electronic Structurementioning

confidence: 99%

Adsorption of carbon adatoms to graphene and its nanoribbons

Ataca

Aktürk

Şahin

et al. 2011

Journal of Applied Physics

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Adsorption and diffusion of 3d transition metal atoms on the GaN (0001) This paper investigates the adsorption of carbon adatoms on graphene and its nanoribbons using first-principles plane wave calculations within density functional theory. The stability at high carbon adatom coverage, migration, and cluster formation of carbon atoms are analyzed. Carbon adatoms give rise to important changes in electronic and magnetic properties even at low coverage. While bare graphene is nonmagnetic semimetal, it is metallized and acquires magnetic moment upon coverage of carbon adatoms. Calculated magnetic moments vary depending on the coverage of adatoms even for large adatom-adatom distances. Electronic and magnetic properties of hydrogen passivated armchair and zigzag nanoribbons show strong dependence on the adsorption site. We also predict a new type of carbon impurity defect in graphene, which has a small formation energy. Interactions between distant carbon adatoms imply a long ranged interaction.

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Structure and magnetic properties of adatoms on carbon nanotubes

Cited by 94 publications

References 34 publications

Half-Metallic Zigzag Carbon Nanotube Dots

Half-Metallic Zigzag Carbon Nanotube Dots

Modifying the electronic structure of semiconducting single-walled carbon nanotubes byAr+ion irradiation

Adsorption of carbon adatoms to graphene and its nanoribbons

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