Coreprotective halfmetallicity in trilayer graphene nanoribbons. Dec 14, 2015 graphene nanoribbons gnrs are a new class of materials that have promising applications in nextgeneration nanoelectronic and optoelectronic devices 1,2,3. Prediction of twodimensional materials with half metallic dirac cones. Nov 16, 2006 here we predict half metallicity in nanometrescale graphene ribbons by using firstprinciples calculations. We show that this phenomenon is realizable if inplane homogeneous electric fields are applied across the zigzagshaped edges of the graphene nanoribbons, and that their magnetic property can be controlled by the external electric fields. They noted that when doping nanoribbons, edgetype and substitutional doping induce different electronic properties to the systems and, in some cases, half metallic behavior. The halfmetallicity of zigzag graphene nanoribbons with. Periodically functionalized graphene can mimic electronic behavior of edgemodified zgnrs as the edgemodified zigzag carbon chains effectively divide a graphene. Electrical current can be completely spin polarized in a class of materials known as half metals, as a result of the coexistence of metallic nature for. Download citation halfmetallic graphene nanoribbons electrical current can be completely spin polarized in a class of materials known as. Firstprinciples calculations predict that half metallic behaviour can be found in nanometrescale ribbons of graphene, in practically realistic conditions. Graphene nanoribbons reach out to the molecular world. Graphene nanoribbons with zigzag and armchair edges prepared.
Table of contents 1 transport in graphene nanoribbons 2. Pdf on mar 22, 2011, erjun kan and others published graphene. Pascual adds that the spanish collaborators have demonstrated that small variations in the way the graphene nanoribbons are attached to a molecule can alter its magnetic properties. Zgnr half turns to half metal when it is wider than 12zigzag chains. Up to now, halfmetallic property has been found not only in some ferromagnetic metals, such as manganese perovskites 1 and heusler. One of the most recent advancements is the development of graphene nanoribbons gnrs layers of graphene with ultrathin width of less than 50 nm. We show that this phenomenon is realizable if inplane homogeneous electric fields are applied across the zigzagshaped edges of the graphene nanoribbons, and that their magnetic properties can be controlled by the external electric fields. Half metals, playing an important role in spintronics, can be described as materials that enable fully spinpolarized electrical current. Half metallic materials are characterized by the coexistence of metallic behaviour for one electron spin and insulating behaviour. Dec 15, 2015 researchers have succeeded in experimentally realizing metallic graphene nanoribbons gnrs that are only 5 carbon atoms wide. Although many chemical modification schemes for achieving half metallicity in zigzagedged graphene nanoribbons zgnrs have been proposed, practically, half metallic transport is hardly observable with them due to the resulting negligible energy difference of the antiferromagnetic af and ferromagnetic f configurations between the two edges.
Efficient synthesis of graphene nanoribbons sonochemically. The nanoribbons are characterized by ms, uvvis, and scanning tunneling microscopy stm. Pdf introduction to quantumatk atk reference manual docs tutorials tubes, ribbons and other 1d nanostructures transport in graphene nanoribbons transport in graphene nanoribbons version. Enhanced half metallicity in the zigzag graphene nanoribbons by adsorption of the zigzag hydrogen fluoride molecular chains. Electrical current can be completely spin polarized in a class of materials known as halfmetals, as a result of the coexistence of. Enhanced half metallicity in edgeoxidized zigzag graphene. To this end, we study, from first principles, six different oxidation schemes of a 1. Templated growth technique produces graphene nanoribbons with. Enhanced halfmetallicity in edgeoxidized zigzag graphene nanoribbons oded hod, vero. Dec 15, 2015 graphene nanoribbons have been suggested as ideal wires for use in future nanoelectronics. In their article, the research team demonstrated fabrication of the. Future studies will focus on all graphene devices combining both metallic and semiconducting graphene nanostructures. High quality graphene nanoribbons epitaxially grown on the sidewalls of silicon carbide sic. Materials design of halfmetallic graphene and graphene.
For example, half metallicity has been predicted in hydrogenterminated zigzag. Based on their size and geometry, they possess unique electromagnetic properties and tunable band gaps which are nanodevice relevant. Scuseria department of chemistry, rice university, houston, texas 770051892. Nano letters enhanced halfmetallicity in edgeoxidized. Nov 16, 2006 firstprinciples calculations predict that half metallic behaviour can be found in nanometrescale ribbons of graphene, in practically realistic conditions. We identify the bisanthrene isomer of the c 28h 14 molecule to be the smallest graphene derivative to present a spinpolarized ground state. Electronic transport in graphene nanoribbons melinda young han this dissertation examines the electronic properties of lithographically fabricated graphene anoribbons gnrs with widths in the tens of nanometers. The properties of graphene nanoribbons are dependent on both the nanoribbon width and the crystallographic orientation of the edges. Molecular dynamics simulation of melting and vacancy. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals.
Using screened exchange density functional theory, we show that these oxidized ribbons are more stable than hydrogenterminated nanoribbons except for the case of. As a result, a decade after the first experimental studies of graphene, there is an active discussion of. Mar 24, 2016 as electronic components are becoming ever smaller, the industry is gradually approaching the limits of what is achievable using the traditional approach with silicon as a semiconductor material. Intrinsic half metallicity in modified graphene nanoribbons. Graphene has been established as one of the strongest materials ever measured 8. These metrics are regularly updated to reflect usage leading up to the last few days. Electronic structures of zigzag edged graphene nanoribbons zgnrs doped with boron b or nitrogen n atoms are investigated by spin polarized firstprinciples calculations. The earliest theoretical studies of graphene nanoribbons, using a simple tightbinding method, predicted that of the armchair nanoribbons, whose width index satisfies is an integer, are metallic, and another are semiconductor with band gaps depending on their width, while all zigzag nanoribbons are metallic, a similar behavior as carbon nanotubes cnts. It is experimentally shown that graphene has unusually high thermal conductivity 67. The observed half metallic character with enhanced stability present fzgnr as a better candidate than pristine zgnr towards the. Exploration of half metallicity in edgemodified graphene nanoribbons. A new scheme is identified to achieve full half metallicity in zgnrs.
Mar 21, 2011 a new templated growth technique for fabricating nanoribbons of epitaxial graphene has produced structures just 15 to 40 nanometers wide that conduct current with almost no resistance. Low temperature and temperaturedependent measurements reveal a length and orientation. Graphene nanoribbons exfoliated from graphite surface. Building halfmetallicity in graphene nanoribbons by. Dec 16, 2015 graphene nanoribbons have been suggested as ideal wires for use in future nanoelectronics. Various microscopic studies of these novel structures showed a high tendency to selfassemble. Pdf intrinsic halfmetallicity in modified graphene nanoribbons. All the calculations presented in this work were carried out. For fe and v atoms, both feld and vld show spinpolarized half metallic properties. The oxidation schemes considered include hydroxyl, lactone, ketone, and ether groups. Synthesis of graphene nanoribbons with selective edge orientation and terminal groups, however, is experimentally challenging. Ballistic tracks in graphene nanoribbons dtu orbit. When the size of the wire is reduced to the atomic scale, graphene is expected to outperform copper in terms of conductance and resistance to electromigration, which is the typical breakdown mechanism in thin metallic wires. Jan 04, 2016 graphene nanoribbons have been suggested as ideal wires for use in future nanoelectronics.
A new synthetic strategy toward novel linear twodimensional graphene nanoribbons up to 12 nm has been established. Jul 12, 2007 we present a comprehensive theoretical study of the electronic properties and relative stabilities of edgeoxidized zigzag graphene nanoribbons. Scanning tunneling microscope lithography is a method which is able to create graphene nanoribbons with well defined edge orientation, having a width of a few nanometers. Unveiling the magnetic structure of graphene nanoribbons rebeca ribeiro,1 jeanmarie poumirol,1 alessandro cresti,2 walter escof. A new paradigm to halfmetallicity in graphene nanoribbons arxiv. For fe and v atoms, both feld and vld show spinpolarized halfmetallic properties.
Realizing robust halfmetallic transport with chemically. Graphene ribbons were introduced as a theoretical model by mitsutaka fujita and coauthors to examine the edge and nanoscale size effect in graphene. Inhomogeneous straininduced halfmetallicity in bent zigzag. Materials design of halfmetallic graphene and graphene nanoribbons. Graphene nanoribbons go metal at precise widths materials today.
Controlling halfmetallicity of graphene nanoribbons by. Twodimensional graphene nanoribbons journal of the. Graphene also has unique thermal and mechanical properties. Graphene nanoribbons gnrs are quasionedimensional strips of graphene with widths on the nanometer scale. Dec 16, 2015 these results open the door to using graphene in future electronic devices, where these ultranarrow ribbons could replace copper as the interconnect material.
Graphene is a oneatomiclayer thick twodimensional material made of carbon atoms arranged in a honeycomb structure. Raman spectroscopy in graphene and nanoribbons scientific. Layerselective halfmetallicity in bilayer graphene nanoribbons. Zgnrhalf turns to half metal when it is wider than 12zigzag chains. Solution synthesis of atomically precise graphene nanoribbons in. Exploration of half metallicity in edgemodified graphene. First, a short introduction of graphene crystal structure and phonon dispersion is given. Will metallic graphene nanoribbons someday replace copper. The spinpolarized electronic structure and half metallicity of zigzag graphene nanoribbons zgnrs with asymmetric edge terminations are investigated by using first principles calculations. Apr 18, 2016 graphene nanoribbons gnr also called nanographite ribbons carbon based material onedimensional structures with hexagonal two dimensional carbon lattices a derivative of graphene graphene ribbons were introduced as a theoretical model by mitsutaka fujita 9 10. Its fascinating electrical, optical, and mechanical properties ignited enormous interdisciplinary interest from the physics, chemistry, and materials science fields.
We find that zgnrs can be tuned to be either semiconducting, half metallic, or metallic by controlling the distance of the impurity atoms to the edges. Enhanced halfmetallicity in edgeoxidized zigzag graphene. Graphene nanoribbons exfoliated from graphite surface dislocation bands by electrostatic force anton n sidorov1, 23, tanesh bansal,pjouseph1 and gamini sumanasekera1,4 1 department of physics, university of louisville, louisville, ky 40292, usa 2 department of electrical and computer engineering, university of louisville, ky 40208, usa. Sep 16, 2014 the successful fabrication of single layered graphene has generated a great deal of interest and research into graphene in recent years. Firstorder and the double resonance raman scattering mechanism in graphene are discussed to understand the most prominent raman peaks. Taking place in graphene based materials, half metallicity has been shown in zigzagedged graphene nanoribbons zgnrs under an electric field.
Halfmetallic graphene nanoribbons youngwoo son, 1,2marvin l. Halfmetallicity in edgemodified zigzag graphene nanoribbons. Unveiling the magnetic structure of graphene nanoribbons. Alkalicreated rich properties in grapheme nanoribbons. Louie1,2 1department of physics, university of california at berkeley, berkeley, california 94720, usa 2materials sciences division, lawrence berkeley national laboratory, berkeley, california 94720, usa dated. Louie1,2 1department of physics, university of california at berkeley, berkeley, california 94720, usa. Here we predict half metallicity in nanometrescale graphene ribbons by using firstprinciples calculations. Efficient synthesis of graphene nanoribbons sonochemically cut from graphene sheets zhongshuai wu, wencai ren, libo gao, bilu liu, jinping zhao, and huiming cheng shenyang national laboratory for materials science, institute of metal research, chinese academy of sciences, 72 wenhua road, shenyang 110016, china. Graphene nanoribbons have been largely studied theoretically, experimentally and with the perspective of electronic applications. Spintronic transport in armchair graphene nanoribbon with.
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