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《NPG Asia Mater. 1(1) 17–21 (2009) The electronic properties of graphene and carbon nanotubes.pdf》由會員上傳分享，免費在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、REVIEWARTICLENPGAsiaMater.1(1)17–21(2009)doi:10.1038/10.1038/asiamat.2009.1TheelectronicpropertiesofgrapheneandcarbonnanotubesTsuneyaAndo*TokyoInstituteofTechnology,JapanAbriefreviewisgivenonthecharacteristicfeaturesofelectronicstatesandtransportingrapheneconsistingofa
2、singlesheetofgraphite,anditscylinderformcalledacarbonnanotube.ElectronmotioningrapheneisequivalenttothatofaneutrinoorarelativisticDiracelectronwithvanishingrestmass.ThiscausestheappearanceofanontrivialBerry’sphaseunder2πrotationinwave-vectorspace,leadingtotheabsenceofb
3、ackscatteringandinthemetalliccarbonnanotuberesultinginperfectconductioneveninthepresenceofscatterers.TheenergybandsincarbonnanotubesaredeterminedbyperiodicboundaryconditionswithafictitiousAharonov-Bohmfluxdetermineduniquelybythecircumferentialchiralvector.Ananotubebeco
4、mesmetallicwhenthefluxvanishesandsemiconductingwhenthefluxisnonzero.TheconductivityofgrapheneisessentiallyindependentoftheFermienergyandtheelectronconcentrationaslongasvariationsineffectivescatteringstrengthareneglected,andthereforegrapheneshouldberegardedasametalrathe
5、rthanazero-gapsemiconductor.Variousschemesarenowbeingproposedandtestedforthepurposeofopeningthebandgapingraphene.hebestknowncarboncrystalisdiamond,whosehardnessandPrimitivetranslationvectorsThighdispersionoflightmakeitusefulforindustrialapplicationsArmchairandjewelry.U
6、nderambientpressuresandatroomtemperature,bhowever,themoststableformofcarbonisgraphite,whichisusedaasanindustriallubricantandasthe‘lead’inpencils.GraphiteisalayeredmaterialinwhicheachlayerconsistsofasheetofcarbonatomsAforminghexagonalstructuressimilartobenzenerings.Amon
7、olayerBLofgraphiteiscalledgraphene,andacarbonnanotubeisacylinderChiralUnitcellmadeofgraphene.vectorCarbonnanotubeswerediscoveredbySumioIijimaduringthesynthesisoffullereneC60in1991.AnanotubeexhibitsextraordinaryChiralmechanicalpropertiesthatmakeitidealforreinforcedcompo
8、sites:itηanglehasahugeYoungmodulus,isasstiffasdiamondandtheestimatedZigzagtensilestrengthismorethantentimesthatofstee
