Graphene nanoribbons exfoliated from graphite surface. Future studies will focus on all graphene devices combining both metallic and semiconducting graphene nanostructures. Unveiling the magnetic structure of graphene nanoribbons. Efficient synthesis of graphene nanoribbons sonochemically. Enhanced halfmetallicity in edgeoxidized zigzag graphene nanoribbons oded hod, vero. 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. Based on their size and geometry, they possess unique electromagnetic properties and tunable band gaps which are nanodevice relevant. Exploration of half metallicity in edgemodified graphene nanoribbons. Edgemodified zigzag graphene nanoribbons zgnr are investigated.
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. Realizing robust halfmetallic transport with chemically. Nov 16, 2006 firstprinciples calculations predict that half metallic behaviour can be found in nanometrescale ribbons of graphene, in practically realistic conditions. Table of contents 1 transport in graphene nanoribbons 2. Electronic structures of zigzag edged graphene nanoribbons zgnrs doped with boron b or nitrogen n atoms are investigated by spin polarized firstprinciples calculations. 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. The nanoribbons are characterized by ms, uvvis, and scanning tunneling microscopy stm. Synthesis of graphene nanoribbons with selective edge orientation and terminal groups, however, is experimentally challenging. Through patterned chemical modification, we show that both graphene sheets and zigzagedged graphene nanoribbons zgnrs can be converted to half metals as long as the unmodified carbon strip or width of zgnrs is sufficiently wide. Graphene has been established as one of the strongest materials ever measured 8. All the calculations presented in this work were carried out. The observed half metallic character with enhanced stability present fzgnr as a better candidate than pristine zgnr towards the.
Scuseria department of chemistry, rice university, houston, texas 770051892. A new scheme is identified to achieve full half metallicity in zgnrs. Graphene also has unique thermal and mechanical properties. For example, half metallicity has been predicted in hydrogenterminated zigzag. 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. Firstprinciples calculations predict that half metallic behaviour can be found in nanometrescale ribbons of graphene, in practically realistic conditions. Unveiling the magnetic structure of graphene nanoribbons rebeca ribeiro,1 jeanmarie poumirol,1 alessandro cresti,2 walter escof. Solution synthesis of atomically precise graphene nanoribbons in. Halfmetallicity in edgemodified zigzag graphene nanoribbons. Electrical current can be completely spin polarized in a class of materials known as halfmetals, as a result of the coexistence of.
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. Controlling halfmetallicity of graphene nanoribbons by. Inhomogeneous straininduced halfmetallicity in bent zigzag. Coreprotective halfmetallicity in trilayer graphene nanoribbons. To this end, we study, from first principles, six different oxidation schemes of a 1. Graphene nanoribbons go metal at precise widths materials today. Building halfmetallicity in graphene nanoribbons by. Firstorder and the double resonance raman scattering mechanism in graphene are discussed to understand the most prominent raman peaks. Enhanced halfmetallicity in edgeoxidized zigzag graphene. 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. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals. For fe and v atoms, both feld and vld show spinpolarized halfmetallic properties.
Prediction of twodimensional materials with half metallic dirac cones. Zgnrhalf turns to half metal when it is wider than 12zigzag chains. 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. Using screened exchange density functional theory, we show that these oxidized ribbons are more stable than hydrogenterminated nanoribbons except for the case of. 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. In their article, the research team demonstrated fabrication of the. Pdf on mar 22, 2011, erjun kan and others published graphene. Jan 04, 2016 graphene nanoribbons have been suggested as ideal wires for use in future nanoelectronics. Raman spectroscopy in graphene and nanoribbons scientific.
First, a short introduction of graphene crystal structure and phonon dispersion is given. One of the most recent advancements is the development of graphene nanoribbons gnrs layers of graphene with ultrathin width of less than 50 nm. Graphene nanoribbons have been largely studied theoretically, experimentally and with the perspective of electronic applications. Ballistic tracks in graphene nanoribbons dtu orbit. The halfmetallicity of zigzag graphene nanoribbons with. A new paradigm to halfmetallicity in graphene nanoribbons arxiv. Intrinsic half metallicity in modified graphene 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. Twodimensional graphene nanoribbons journal of the.
Spintronic transport in armchair graphene nanoribbon with. Periodically functionalized graphene can mimic electronic behavior of edgemodified zgnrs as the edgemodified zigzag carbon chains effectively divide a graphene. Here we predict half metallicity in nanometrescale graphene ribbons by using firstprinciples calculations. Graphene nanoribbons reach out to the molecular world.
It is experimentally shown that graphene has unusually high thermal conductivity 67. Enhanced half metallicity in edgeoxidized zigzag graphene. Layerselective halfmetallicity in bilayer graphene nanoribbons. 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. Louie1,2 1department of physics, university of california at berkeley, berkeley, california 94720, usa. Dec 16, 2015 graphene nanoribbons have been suggested as ideal wires for use in future nanoelectronics. 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. Its fascinating electrical, optical, and mechanical properties ignited enormous interdisciplinary interest from the physics, chemistry, and materials science fields. Jul 12, 2007 we present a comprehensive theoretical study of the electronic properties and relative stabilities of edgeoxidized zigzag graphene nanoribbons.
Molecular dynamics simulation of melting and vacancy. Templated growth technique produces graphene nanoribbons with. The spinpolarized electronic structure and half metallicity of zigzag graphene nanoribbons zgnrs with asymmetric edge terminations are investigated by using first principles calculations. They noted that when doping nanoribbons, edgetype and substitutional doping induce different electronic properties to the systems and, in some cases, half metallic behavior. To harness these characteristics of gnrs, it is essential to produce them with atomic precision. 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. Nano letters enhanced halfmetallicity in edgeoxidized. Materials design of halfmetallic graphene and graphene.
Half metallic materials are characterized by the coexistence of metallic behaviour for one electron spin and insulating behaviour. Download citation halfmetallic graphene nanoribbons electrical current can be completely spin polarized in a class of materials known as. For fe and v atoms, both feld and vld show spinpolarized half metallic properties. A new synthetic strategy toward novel linear twodimensional graphene nanoribbons up to 12 nm has been established. 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. Up to now, halfmetallic property has been found not only in some ferromagnetic metals, such as manganese perovskites 1 and heusler.
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. Half metals, playing an important role in spintronics, can be described as materials that enable fully spinpolarized electrical current. 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. Graphene nanoribbons gnrs are quasionedimensional strips of graphene with widths on the nanometer scale. Exploration of half metallicity in edgemodified graphene. Intrinsic halfmetallicity in modified graphene nanoribbons. As a result, a decade after the first experimental studies of graphene, there is an active discussion of. Half metallicity recently predicted in the zigzagedge graphene nanoribbons zgnrs and the hydrogenated carbon nanotubes cnts enables fully spinpolarized electric currents, providing a basis for carbonbased spintronics. Graphene ribbons were introduced as a theoretical model by mitsutaka fujita and coauthors to examine the edge and nanoscale size effect in graphene. Pdf intrinsic halfmetallicity in modified graphene nanoribbons. 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. Various microscopic studies of these novel structures showed a high tendency to selfassemble. Sep 16, 2014 the successful fabrication of single layered graphene has generated a great deal of interest and research into graphene in recent years.
High quality graphene nanoribbons epitaxially grown on the sidewalls of silicon carbide sic. Dec 15, 2015 researchers have succeeded in experimentally realizing metallic graphene nanoribbons gnrs that are only 5 carbon atoms wide. Ultranarrow metallic armchair graphene nanoribbons nature. Materials design of halfmetallic graphene and graphene nanoribbons. Halfmetallic graphene nanoribbons youngwoo son, 1,2marvin l. 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. Metalfree boron nitride nanoribbon catalysts for electrochemical co2 reduction. Low temperature and temperaturedependent measurements reveal a length and orientation. Graphene nanoribbons with zigzag and armchair edges prepared. Dec 15, 2015 graphene nanoribbons have been suggested as ideal wires for use in future nanoelectronics.
Will metallic graphene nanoribbons someday replace copper. The properties of graphene nanoribbons are dependent on both the nanoribbon width and the crystallographic orientation of the edges. 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. We identify the bisanthrene isomer of the c 28h 14 molecule to be the smallest graphene derivative to present a spinpolarized ground state. Graphene is a oneatomiclayer thick twodimensional material made of carbon atoms arranged in a honeycomb structure. Graphene nanoribbons gnrs, also called nano graphene ribbons or nanographite ribbons are strips of graphene with width less than 50 nm. Zgnr half turns to half metal when it is wider than 12zigzag chains. Taking place in graphene based materials, half metallicity has been shown in zigzagedged graphene nanoribbons zgnrs under an electric field. Nov 16, 2006 here we predict half metallicity in nanometrescale graphene ribbons by using firstprinciples calculations. Alkalicreated rich properties in grapheme nanoribbons. 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. These metrics are regularly updated to reflect usage leading up to the last few days.