碳氮硼基低維體系的自旋輸運性質(zhì)研究

碳氮硼基低維體系的自旋輸運性質(zhì)研究碳氮硼基低維體系的自旋輸運性質(zhì)研究

摘要：

近年來，低維自旋系統(tǒng)在量子信息處理和磁性存儲等應(yīng)用中備受關(guān)注。碳氮硼基材料因其良好的化學(xué)特性和獨特的電子結(jié)構(gòu)，成為低維自旋器件的重要候選材料。本文研究了碳氮硼基低維體系（包括石墨烯、碳納米管和硼氮烷）的自旋輸運性質(zhì)，通過第一性原理計算，探討了自旋相關(guān)電子結(jié)構(gòu)、自旋輸運行為、自旋-軌道耦合和自旋阻塞等重要問題。研究結(jié)果表明，在碳氮硼基低維體系中，自旋輸運性質(zhì)顯著受到材料結(jié)構(gòu)和摻雜控制的影響，尤其是摻雜引入的雜質(zhì)和缺陷對自旋輸運的影響較大。此外，石墨烯和碳納米管中的自旋-軌道耦合較弱，而硼氮烷則存在強烈的自旋-軌道耦合效應(yīng)。本文研究結(jié)果有望為碳氮硼基低維自旋器件的設(shè)計和優(yōu)化提供指導(dǎo)。

關(guān)鍵詞：碳氮硼基材料、低維體系、自旋輸運、自旋-軌道耦合、自旋阻塞、第一性原理計算。

Abstract:

Inrecentyears,low-dimensionalspinsystemshavebeenwidelystudiedduetotheirpotentialapplicationsinquantuminformationprocessingandmagneticstorage.Carbon,nitrogenandboron-basedmaterialsareimportantcandidatesforlow-dimensionalspindevicesduetotheirexcellentchemicalpropertiesanduniqueelectronicstructures.Inthispaper,weinvestigatedthespintransportpropertiesofcarbon,nitrogenandboron-basedlow-dimensionalsystems(includinggraphene,carbonnanotubesandboronnitride)byfirst-principlescalculations,exploringimportantissuessuchasspin-correlatedelectronicstructures,spintransportbehaviors,spin-orbitcouplingandspinblockade.Theresultsshowthatthespintransportpropertiesinthecarbon,nitrogenandboron-basedlow-dimensionalsystemsaresignificantlyaffectedbythematerialstructureanddopingcontrol,especiallytheimpuritiesanddefectsintroducedbydopinghaveasignificantimpactonspintransport.Inaddition,grapheneandcarbonnanotubesexhibitweakspin-orbitcoupling,whileboronnitridedisplaysstrongspin-orbitcoupling.Theresultsinthispapermayprovideguidanceforthedesignandoptimizationofcarbon,nitrogenandboron-basedlow-dimensionalspindevices.

Keywords:carbon,nitrogenandboron-basedmaterials,low-dimensionalsystem,spintransport,spin-orbitcoupling,spinblockade,first-principlescalculations。Inrecentyears,thestudyofspintransportinlow-dimensionalsystemshasreceivedmuchattentionduetoitspotentialapplicationsinspintronics,whichaimstodevelopdevicesthatexploitthespinofelectronsinsteadoftheircharge.Theuseoflow-dimensionalmaterialssuchasgraphene,carbonnanotubes,andboronnitridehasshownpromisingresultsinachievingefficientspintransport.

Thepresentstudyinvestigatedtheimpactofspin-orbitcouplingonspintransportincarbon,nitrogen,andboron-basedlow-dimensionalsystems.Theresultsshowedthatthepresenceofspin-orbitcouplingledtotheformationofspinblockade,whichreferstothesuppressionofspintransportduetotheconservationofspinangularmomentum.

Thestudyalsofoundthatthestrengthofspin-orbitcouplingdependsonthetypeofmaterialused.Carbon-basedmaterialssuchasgrapheneandcarbonnanotubesexhibitedweakspin-orbitcoupling,whileboronnitridedisplayedstrongspin-orbitcoupling.Thisfindingsuggeststhatthechoiceofmaterialisacrucialfactorindesigningandoptimizinglow-dimensionalspindevices.

Thestudywascarriedoutusingfirst-principlescalculations,whicharebasedonthefundamentallawsofquantummechanics.Themodelsusedinthecalculationswererealisticandtookintoaccountthecomplexelectronicstructureofthematerials.Theresultsprovidevaluableinsightsintothebehaviorofspintransportinlow-dimensionalsystemsandmayguidefutureresearchinthisfield.

Inconclusion,thisstudyhighlightstheimportanceofspin-orbitcouplinginlow-dimensionalspintransportanddemonstratesthepotentialofcarbon,nitrogen,andboron-basedmaterialsinspintronics.Thefindingsmaypavethewayforthedevelopmentofnovelspin-baseddeviceswithenhancedperformanceandefficiency。Furthermore,thestudyalsoshedslightonthechallengesandlimitationsfacedinthefieldofspintronics.Oneofthemajorchallengesisthedevelopmentofefficientmethodsforgeneratingandcontrollingspincurrents.Currently,mostresearchinthisfieldisfocusedonusingexternalmagneticfieldsorelectricalcurrentstogenerateandmanipulatespincurrents.However,thesemethodsarenotveryefficientandcanleadtosignificantenergylosses.

Toovercomethesechallenges,researchersareexploringnewmaterialsandnovelphysicalphenomenathatmayenablemoreefficientspintransportandmanipulation.Forexample,recentstudieshaveshownthattopologicalinsulators,whicharematerialsthatconductelectricityontheirsurfacesbutareinsulatinginthebulk,mayhaveuniquepropertiesthatmakethemidealforspintronicsapplications.Inaddition,researchersarealsoinvestigatingthepossibilityofusingspin-orbittorque,whichisaphenomenonthatoccurswhenaspincurrentexertsatorqueonamagneticmaterial,tomanipulatethemagneticstatesofdevices.

Overall,thefieldofspintronicshasthepotentialtorevolutionizethewayweprocessandstoreinformation,andthefindingsofthisstudyprovidevaluableinsightsintothebehaviorofspincurrentsinlow-dimensionalsystems.However,therearestillmanychallengestobeovercomebeforespin-baseddevicesbecomeareality,andresearchersmustcontinuetoexplorenewmaterialsandphenomenatoenablemoreefficientspintransportandmanipulation。Oneofthechallengesindevelopingspintronicsdevicesisthefabricationofmaterialswithsuitablemagneticandspintransportproperties.Currently,mostspintronicsresearchfocusesonstudyingthebehaviorofspinsintransitionmetalferromagnetssuchasiron,cobalt,andnickel.However,thesematerialshavelimitationsintermsoftheirstabilityandabilitytomaintaintheirmagneticpropertiesatroomtemperature.

Toaddressthesechallenges,researchershaveexploredalternativematerialsandphenomena,suchastopologicalinsulatorsandmagneticskyrmions.Topologicalinsulatorsarematerialsthathaveabulkinsulatingbehaviorbutconductelectricityontheirsurfacesduetothepresenceoftopologicalsurfacestates.Thesesurfacestateshaveauniquespin-momentumlockingpropertythatcanbeexploitedforspintransportandmanipulation.

Meanwhile,magneticskyrmionsaretopologicallyprotected,nanoscalemagneticstructuresthatcanbeusedforinformationstorageandprocessing.Thesemagneticstructuresexhibitauniquegeometricalarrangementofspins,whichmakesthemhighlystableandrobustagainstexternalperturbations.

Inadditiontonovelmaterials,anotherchallengeinspintronicsistheefficientmanipulationofspincurrents.Thisrequiresthedevelopmentofnewtechniquesforgenerating,detecting,andcontrollingspincurrents.Spininjectionanddetectiontechniques,suchasspinHalleffectandinversespinHalleffect,havebeenwidelystudiedandcontinuetobeimproved.Meanwhile,advancedfabricationtechniques,suchaselectron-beamlithographyandfocusedionbeam,enablepreciseengineeringofmaterialsanddevicesatthenanoscalelevel.

Overall,thefieldofspintronicsholdsimmensepotentialfordevelopingnext-generationdevicesthatarefaster,moreenergy-efficient,andcapableofhandlinglargeamountsofdata.However,therearestillmanychallengesthatneedtobeovercomebeforespintronicstechnologybecomesubiquitousinourdailylives.Withcontinuedresearchanddevelopment,wecanhopetoseetheemergenceofnewmaterialsandphenomenathatenablemoreefficientspintransportandmanipulation,andthetranslationoftheseideasintopracticaldevices。Oneofthemainchallengesfacingspintronicstechnologyisthedifficultyingenerating,detecting,andmanipulatingspinswithhighprecisionandefficiency.Forinstance,inordertocreateaspincurrent,oneneedstoapplyanexternalmagneticfield,whichcanbecumbersomeandimpracticalforpracticalapplications.Similarly,detectingthespinorientationofelectronsrequiresspecializedtechniquessuchasspin-dependenttunnelingormagnetoresistancemeasurements,whichmaynotbescalableorreliableinallsituations.

Anotherchallengewithspintronicsisthelimitedrangeofmaterialsthatexhibitspin-dependenttransportproperties.Currently,onlyahandfulofmaterialssuchasferromagneticmetals,semiconductors,andtopologicalinsulatorshavebeenidentifiedaspromisingcandidatesforspintronicsdevices.However,eachofthesematerialshasitsownlimitations,suchaslowspinlifetime,lowspindiffusionlength,orlowspininjectionefficiency.Inordertoovercometheselimitations,researchersneedtoexplorenewmaterialsandphenomenathatcanofferbetterspintransportandmanipulationproperties.

Furthermore,oneofthekeyobstaclesinspintronicsisintegratingspin-baseddeviceswithconventionaldigitalcircuits.Althoughspin-baseddevicesoffermanyadvantagesoverconventionalelectronicssuchasnon-volatility,lowpowerconsumption,andhighspeed,theyarecurrentlydifficulttointegratewithexistingCMOStechnology.ThisisbecauseCMOStechnologyoperatesonafundamentallydifferentworkingprinciplethanspin-baseddevices,andrequiressignificantmodificationsinordertointegratespin-baseddevicesonthesamechip.Thischallengeisfurthercompoundedbythefactthatspin-baseddevicesareoftensensitivetoexternalmagneticfields,temperaturefluctuations,andotherenvironmentalfactorsthatcanaffecttheirperformance.

Despitethesechallenges,thepotentialbenefitsofspintronicstechnologyaretoogreattoignore.Spin-baseddeviceshavealreadydemonstratedarangeofpromisingapplications,includingmagneticmemory,spinvalves,magneticsensors,andevenspin-basedlogiccircuits.Withthecontinueddevelopmentofnewmaterials,fabricationtechniques,anddevicearchitectures,thereisagoodchancethatspintronicstechnologywillbecomeincreasinglyprevalentinthecomingyears.

Inconclusion,spintronicstechnologyrepresentsanexcitingnewareaofresearchthathasthepotentialtorevolutionizethewaywestore,process,andtransmitinformation.However,therearestillsignificantchallengesthatneedtobeovercomebeforespin-baseddevicesbecomeasubiquitousastraditionalelectronicdevices.Addressingthesechallengeswillrequireinnovativesolutions,interdisciplinarycollaborations,andawillingnesstoexplorenewmaterialsandphenomena.Withcontinuedresearchanddevelopment,wecanhopetoseetheemergenceofspin-baseddevicesthatarefaster,moreenergy-efficient,andcapableofhandlingmassiveamountsofdata,pavingthewayforaneweraofcomputingandcommunication。Oneofthekeychallengesfacingthedevelopmentofspin-baseddevicesisthelackofsuitablematerials.Whilesomematerials,suchasironandcobalt,exhibitstrongspinpolarization,theyarenotsuitableforuseinelectronicdevicesduetotheirpoorelectricalproperties.Othermaterials,suchasgrapheneandcarbonnanotubes,showpromiseforspintronicsapplications,butarestillintheearlystagesofdevelopment.

Toovercomethesechallenges,researchersareexploringarangeofnewmaterialsandphenomena.Onepromisingapproachistousetopologicalinsulators,whicharematerialsthatconductelectricityontheirsurfacebutareinsulatorsintheirinterior.Thesematerialshaveuniquepropertiesthatcouldenablethecreationofnewtypesofspintronicdevices,suchasspin-basedtransistorsandmemorydevices.

Anotherapproachistoexploretheuseof2Dmaterials,suchastransitionmetaldichalcogenides.Thesematerialshaveuniqueproperties,suchasstrongspin-orbitcoupling,thatcouldmakethemidealforuseinspintronicsapplications.Researchersarealsoexploringtheuseofothermaterials,suchasmagneticsemiconductorsandtopologicalsemimetals,thatcouldhaveimportantrolestoplayinthedevelopmentofspin-baseddevices.

Inadditiontodevelopingnewmaterials,researchersarealsoexploringnewphenomenathatcouldbeusedtocreatemoreefficientandpowerfulspintronicsdevices.Onepromisingareaofresearchistheuseofspin-orbittorques,whichinvolvethetransferofspinangularmomentumtoelectriccurrentandviceversa.Thisphenomenoncouldbeusedtocreatehighlyefficientandlow-powerdevices,suchasspin-basedlogicgates.

Interdisciplinarycollaborationsarealsocriticaltothedevelopmentofspin-baseddevices.Researchersinphysics,materialsscience,electricalengineering,andotherfieldsareworkingtogethertodevelopnewmaterials,explorenewphenomena,andcreatenewdevices.Bringingtogetherdiverseperspectivesandexpertiseiskeytoovercomingthecomplexchallengesfacingthefield.

Inconclusion,thefieldofspintronicsholdsgreatpromiseforthedevelopmentoffaster,moreefficient,andmorepowerfulelectronicdevices.Whiletherearestillmanychallengestobeovercome,researchersaremakingsteadyprogressindevelopingnewmaterials,exploringnewphenomena,andcreatingnewdevices.Withcontinuedresearchandcollaborations,wecanexpecttoseespin-baseddevicesbecomemoreubiquitousinthecomingyears,pavingthewayforaneweraofcomputingandcommunication。Oneexcitingareaofspintronicsresearchinvolvesthedevelopmentofspin-basedmemorydevices.Unlikeconventionalcomputermemory,whichreliesonelectricchargetostoreinformation,spin-basedmemoryusestheorientationofelectronspinstorepresent1sand0s.Thisapproachoffersseveraladvantages,includingfasterreadandwritespeeds,lowerpowerconsumption,andgreaterdurability.

Onetypeofspin-basedmemorydevicethathasgarneredsignificantattentionisthemagneticrandom-accessmemory(MRAM).MRAMisanon-volatilememorytechnology,meaningthatitcanretainstoredinformationevenwhenpoweristurnedoff.Thispropertymakesitwell-suitedforuseindevicessuchassmartphones,tablets,andsolid-statedrives.

ResearchershavemadesubstantialprogressinimprovingtheperformanceofMRAMdevices,includingincreasingtheirstoragedensity,reducingtheirpowerconsumption,andimprovingtheirdataretention.In2018,researchersatIBMannouncedthedevelopmentofanewtypeofMRAMdevicethatcouldstoremultiplebitspercell,potentiallyincreasingstoragedensitybyafactoroffourormorecomparedtocurrentMRAMtechnologies.

Anotherareaofspintronicsresearchfocusesontheuseofspintronicdevicesinquantumcomputing.Unlikeclassicalcomputers,whichrepresentinformationusingbitsthatareeither1or0,quantumcomputersusequantumbits(qubits),whichcanbeinasuperpositionofbothstatessimultaneously.Thispropertyallowsquantumcomputerstosolvecertainproblems,suchasfactorizinglargenumbers,muchfasterthanclassicalcomputers.

Spin-basedqubitshaveseveraladvantagesoverothertypesofqubits,includingbeingeasiertocontrolandmaintain.However,developingspin-basedqubitsthatmeetthestringentrequirementsforquantumcomputingremainsasignificantchallenge.Researchersareexploringavarietyofapproachestoaddressthesechallenges,includingusingmaterialswithstrongspin-orbitcoupling,suchastopologicalinsulators,andcombiningspin-basedqubitswithothertypesofqubits,suchassuperconductingqubits.

Beyondmemoryandquantumcomputing,spintroni