南大李俊老师之2010诺贝尔物理奖石墨烯讲解

咱家是如何成功预言今年的诺贝尔物理奖的？李俊百合水人（HigherQM2007）南京大学物理学院教授新浪博客“科学相声大师”演讲主题为什么石墨烯能得诺贝尔奖？为什么石墨烯能得物理学奖而不是化学奖？为什么Geim既能得搞笑诺贝尔奖又能得真的诺贝尔奖？为什么我国110年来没有在本土产生诺贝尔科学奖？为什么石墨烯能得诺贝尔奖?Whygraphene?“thegreatestthingsinceslicedpencillead.”-SheldonCooper“Carbon,thebasisofallknownlifeonearth,hassurprisedusonceagain.”-theRoyalAcademytheexcitementaboutthenewphysicsexperimentsandpossibleapplications.ThesimplestmethodeverusedinaNobel.获奖亮点Itisnotonlythethinnestmaterialintheworld,butalsooneofthestrongestandhardest.toconductelectricityaswellascopperdoesandtoconductheatbetterthananyotherknownmaterial,anditispracticallytransparent.itcouldeventuallyrivalsiliconasabasisforcomputerchips,serveasasensitivepollution-monitoringmaterial,improveflat-screentelevisions,andenablethecreationofnewmaterialsandnoveltestsofquantumweirdness.Nature:Inonesentence,whatisgraphene?Geim:Grapheneisasingleplaneofgraphitethathastobepulledoutofbulkgraphitetoshowitsamazingproperties.NatureNews-Nobellaureateexplainswhythecarbonsheetsdeservedtowinthisyear'sprize.石墨矿（Graphite）样品2008年石墨矿产量全球111万吨中国80万吨美国无石墨矿源1564年，在英格兰的一个叫巴罗代尔的地方，人们发现了一种黑色的矿物-石墨。由于石墨能像铅一样在纸上留下痕迹，而且痕迹比铅的痕迹要黑得多，因此，人们称石墨为“黑铅”。石墨是元素碳的一种同素异形体，是其中最软的矿物，它的用途包括制造铅笔芯和润滑剂，也可作为核电站反应堆的中子减速剂。1761年，德国化学家法伯首先磨石墨粉，然后同硫磺、锑、松香混合，再将这种混合物成条，这比纯石墨条的韧性大得多，也不大容易弄脏手。这就是最早的铅笔。Graphite1789fromtheGreek“graphein”:todraw/write命名者：维尔纳（德国）A.G.Werner地质学科创立者Graphene1962至今词典里没有，命名者：Hanns-PeterBöhmapioneerofgrapheneresearchPeopleallovertheworldisusinggraphitepencils.Whenusinggraphitepencilforwriting,weareallpullingoutseveralatomicplanestogetherfromthegraphiterodofthepencil.Noneofusthinksaboutasingleplaneforthelast500years.Sotheinventionisoneofthemostintuitiveinnature.-AwebreaderofNatureaDiamond钻石bGraphitecLonsdaleite金刚石dC60（1985）1996年诺贝尔化学奖eC540fC70gAmorphousChCnanotube碳家族的八大金刚碳的同素异形体AllotropesScanningtunnelingmicroscopeSTMimageofgraphitesurfaceatomsSTM一九八六年诺贝尔物理奖Ball-and-stickmodelofgraphite2graphenelayers蜂窝晶体结构honeycombstructure石墨的三维晶体结构由二维碳原子层纵向叠加而成，碳原子平面内的每个碳原子的周边连结著另外三个碳原子，排列方式呈蜂巢式的多个六边形。由于每个碳原子均会放出一个电子，这些电子能够自由移动，因此石墨属于导体。由于二维碳原子层之间的耦合比起同一层中碳原子之间的化学键结合小得多，因此，石墨像云母一样，十分容易进行剥离。石墨烯（graphene）就是从石墨中剥（peeloff）出来的单一碳原子层。“Scotchtapetechnique”ThesimplestmethodeverusedGraphene，asingleatomthicksheetofcarbons，wasonlyisolatedin2004afteralongstrugglealthoughgraphitehasbeenstudiedfordecades.Startingwithagraphitecrystal,layersofcarbonatomswerepeeledoffonebyonewithadhesivetape,untilasingle-layerflakewasleft.胶带撕出诺贝尔奖的两个传说《纽约时报》10月5日：atechnicianshowedthemhowgraphitewascleanedbeforebeingobservedinaSTMbypeelinglayersoffwithScotchtape.ScienceWatch.com2008：Geim的中国博士生跟他抬杠：“Ifyou’resoclever,trytodoityourself.”。AGraphenevisualizedbyatomicforcemicroscopy.Thefoldedregionexhibitingarelativeheightof≈4Åclearlyindicatesthatitisasinglelayer.BAgraphenesheetfreelysuspendedonamicrometre-sizemetallicscaffold.Thetransmissionelectronmicroscopyimage.CSTMofarelativelylargegraphenecrystal,whichshowsthatmostofthecrystal’sfacesarezigzagandarmchairedgesasindicatedbyblueandredlinesandillustratedintheinset.1Dtransportalongzigzagedgesattractsignificantattention.MotherofallgraphiticformsWorkopenningtheeraof‘goldrush’ofgrapheneK.S.Novoselov,A.K.Geim,S.V.Morozov,D.Jiang,Y.Zhang,S.V.Dubonos,I.V.Grigorieva,A.A.Firsov(Manchester,UK):ElectricFieldEffectinAtomicallyThinCarbonFilmsSCIENCE306,666(2004).22OCTOBER2004被引频次:3,292为什么石墨烯能得物理学奖?Whyphysicsprize?Groundbreakingexperimentsregardingthetwo-dimensionalmaterialDiracfermion:Anewparadigmofcondensed-matterphysicsQuantumHalleffectsNobelprizes1985，1998MaterialScienceerasingelectronmassThehoneycomblatticepatternofgrapheneexplainsitsstrengthandgoodconductivity.Eachcarbonatomusesthreeofitsoutervalenceelectronstoformstrongcovalentbonds,leavingoneforconduction.HoneycomblatticeanditsBrillouinzoneDiracpoints:Electronicdispersion:Wallace1947抛物线型能量-动量关系石墨烯电子的线性能谱WorkopenningthedoorofgrapheneP.R.Wallace(Ontario,Canada)ThebandtheoryofgraphitePhys.Rev.71,622–634(1947).狄拉克点上的三相交流电Grapheneisaremarkableconductor.Inneutralgraphene,thechemicalpotentialcrossesexactlytheDiracpoint.Thisparticulardispersion,thatisonlyvalidatlowenergies,mimicsthephysicsofquantumelectrodynamics(QED，innovatedbyDirac)forrelativisticmasslessfermionsexceptforthefactthatingraphenetheDiracfermionsmovewithaspeedwhichis300timessmallerthanthespeedoflight.Hence,manyoftheunusualpropertiesofQEDcanshowupingraphenebutatmuchsmallerspeeds.DiscoveringDiracfermionsinMaterialScienceThetwo-componentelectronwavefunction,closetotheDiracKpoint,obeysthe2DDiracequationHencethechargecarriersresponsibleforthelow-energyexcitationsingraphenearemassless,chiral,Diracfermions,whichisitsmostinterestingaspects.G.W.Semenof(Vancouver,Canada):Condensed-mattersimulationofathree(2+1)-dimensionalanomalyPhys.Rev.Lett.53,2449–2452(1984).“relativistic”physicsonapenciltiporliketheLargeHadronCollider,butonyourdesktopAnewparadigmofcondensed-matterphysicsGrapheneisaformofcarbon.Asamaterialitiscompletelynew-notonlythethinnesteverbutalsothestrongest.Asaconductorofelectricityitperformsaswellascopper.Asaconductorofheatitou