凝聚態(tài)物理前沿講座方忠QuantumSimulationintheFieldofSpintronic

方忠中國科學(xué)院物理研究所，理論室

QuantumSimulationintheFieldofSpintronicsandOrbitronicsAcknowledgement:

Y.G.Yao,K.TerakuraN.NagaosaY.Tokura凝聚態(tài)物理前沿講座

Contents1.QuantumsimulationsbasedonDFT

(1)Simpleintroductiontofirst-principlescalculations(2)Ourmethod,code,andcomputerfacilities2.Dissipationlessquantumcurrentforspintronics

(1)AnomalousHallEffect(2)SpinHallCurrent(3)AnomalousNernstEffect3.OrbitonandOrbitronics(1)PhasediagramofLa1-xSrxMnO3(2)Orbital-dependentphasecontrolinCa2-xSrxRuO4(3)Magnetismindoubleperovskites4.Surfaceoftransition-metaloxidesQuantumSimulationbasedonDFTAtoms+electronsElectronsMany-bodyElectronsSingle-particleDensityFunctionalAdiabaticApproximationHohenberg-KohnKohn-ShamHellmann-FeynmanForceandStressMDSCFSelf-consistentSolverforKSproblemSCFLDAGGALDA+ULDA+UmethodPseudopotentialSchemeNormal-conservingPseudopotentialUltra-SoftPseudopotentialVirtualCrystalApproxmation(VCA)ForvirtualatomsSolveSchrodingerequationIonicunscreenedpotentialHowtosolvethesingleparticleproblemRealSpace(noFFT)FiniteelementFinitedifferenceMulti-gridAdaptiveWavelet…ReciprocalSpace(withFFT)LACOLMTOFLAPWPAWPlane-waveGreen’sfunction…Pseudopotential,ASA,…OtherProblemsinSimulationsExchange-correlationfunctionalStrongly-correlatedsystemsForcecalculation&MoleculardynamicsMagnetic,optical&electronicpropertiesExcitedStatesNon-equilibrium&Time-dependentprocessOrder(N)method&LargescaleCatalysis,Chemicalreaction,Bio-systems…First-principlescalculationsbasedonDFTPlane-wavebasisUltra-softPseudo-potentialLDA,GGA,LDA+U,etc…Virtualcrystalapproximation(VCA)RealspaceRMMforlargersystemsFullparallelizationbyMPI

SGI,IBM-SP,Alpha,Cray,VPP,PC-ClusterOurMethod

STATECode:

(SimulationalToolforAtomTechnology) MainContributors:

Z.Fang, Y.Morikawa,T.Ikeda,H.Sawada andotherJRCATmembers

Fordetails:

Z.Fang,et.al,J.Phys:Cond.Matt.,14,3001(2023). (reviewarticle)

～100,000lines,Accuracy～1meV/Atom,～200atoms.WidelyusedinJapan,Taiwan,Korea,Denmark,etc.IBMSP690,64CPUs,128G,1T-diskThreeCharactersofElectron

ChargeSpinOrbitalwellknown“hot”topicnewExtensivelyusedbeingusedwillbeusedI,V,ρ……ChargecurrentChargeexcitationspinwaveorbitonChargecurrentspincurrentmovement……anisotropyfunctionality….SpintronicsTheelectronhasbothchargeandspin.Mostlyonlythechargepropertyisused.

Energyscaleforthechargeinteractionishigh,~1eV,energyscaleforthespininteractionislow,~

10-100meV.

Muchlowerpowerconsumptionforspin-baseddevice.

Spin-basedelectronicsalsopromisesagreaterintegrationbetweenthelogicandstoragedevicesProblemsforSpintronicdevices

spininjectionintosemiconductor

Ohmicinjectionfromferromagnet

Lowefficiency(Difficulty):Ferromagneticmetal:conductivitymismatch

spinpolarizationisalmostlostatinterface.Ferromagneticsemiconductor(e.g.Ga1-xMnxAs):Curietemperaturemuchlowerthanroomtemp.Ferromagnetictunneljunction.

spindetectionbyferromagnet

spintransportinsemiconductorspinrelaxationtimeOpticalpumpandprobeOnlytwoknownexamplesofdissipationlesstransportinsolids!

Supercurrentinasuperconductorisdissipationless,sinceLondonequationrelatedJtoA,nottoE!Vectorpotential=oddunderT,chargecurrent=oddunderT.

IntheQHE,theHallconductivityisproportionaltothemagneticfieldB,whichisoddunderT.Laughlinargument:allstatesbelowthefermienergycontributetotheHallconductance.Stredaformula,TKNNformularelatestheHallconductancetothe1stChernnumber.

Newdissipationlesstransportinsolidsduetospin-orbitalcoupling!?AnomalousHallEffect(chargecurrent):[1]T.Jungwirth,et.al.,PRL,88,207208(2023);

[2]Z.Fang,et.al,SCIENCE,302,92(2023)][3]Y.G.Yao,et.al,PRL,92,37204(2023);[4]W.L.Lee,et.al,SCIENCE,303,1647(2023)]

Conventional:

ρxy=R0H+4πRSM

IntrinsicMechanism:σxyσxy(M)

ThusJx=σxyEyisTinvariantJisodd,Eiseven,Misodd?DissipationlessspinHallcurrent:[1]S.Murakami,et.al,SCIENCE,301,1348(2023);[2]J.E.Hirsch,et.al.,PRL,83,1834(1999)[3]J.Sinova,et.al,PRL,92,126603(2023)[4]S.Q.Shen,et.al.,cond-mat/040305.[5]Y.Xiong&X.C.Xie,cond-mat/0403083.SpincurrentisevenunderTBjHFMjAHEConventionalHallAnomalousHallEESpinjSHEESpinHallMeritofAHEandSHE1.Itworksbecauseofspin-orbitalcoupling,whichisactiveevenatroomT.2.Itisentirelytopological(dissipationless).Spin-OrbitalCouplingBerryPhaseMagneticMonopolesinMomentumSpaceAnomalousHallcurrentandSpinHallcurrent(Botharedissipationless)IntrinsicMechanismEffectiveHamiltonianforadiabatictransportEquationofmotion(Diracmonopole)DriftvelocityTopologicaltermNontrivialspindynamicscomesfromtheDiracmonopoleatthecenterofkspace,witheg=l:Adiabatictransport=potentialVdoesnotcauseinter-bandtransitions

onlyretaintheintra-bandmatrixelementsFullQuantumCalculationsBasedonKuboFormularAnomalousHallconductivitywithSpinHallconductivityJysConservedSpinCurrent(S.Murakami,et.al.,cond-mat/0310005)Conservedspinwhichsatisfydefinecurrenti,n,m=bandindexα,β,γ

=kramersdoubletsindexZ.Fang,et.al.,SCIENCE302,92(2023)反常Hall效應(yīng)與動(dòng)量空間中旳磁單極CalculatedGaugeFluxforkz=0inSrRuO3bz(kz=0)GMMMMZ.Fang,et.al,SCIENCE,302,92(2023)SrRuO3SrRuO3CalculatedSpinHallCurrentinGaAsCalculatedSpinCurrentforGaAsandSnTeOneExampleforHalf-MetalMnAsFullyspinpolarizedanomalousHallcurrentinMnAsSpinconductivityAHEconductivityAnomalousNernstEffectBVFMVConventionalAnomalousInverseAnomalousNernstEffect:CoolingandrefrigeratorFMHeatcurrentjQExHeatcurrent:Eq.ofmotion:egt2g3z2-r2x2-y2xyyzzxOrbitronicsOrbitalDegreesofFreedom(ODF)EnergyDownspinUpspinEFO-2pO-2pt2gt2gegeg2-fold(ODF)3-fold“Half-metal”VariousOrderingsFMA-typeC-typeG-typeLatticeSpinChargeOrbitalSC,TMR,CMR,M-ITransition,AnomalousHallEffect,Magneto-optical,Ferroelectricity,Piezoelectricity,etc…ExperimentalTheoreticalSCIENCE

288,462(2023).J.Phys.Soc.Jap.

68,3790(1999).PhaseDiagramofTetragonalLa1-xSrxMnO3(ControllingofOrbitalandSpinOrderings)Z.Fang&K.Terakura,PRL84,3169(2023).FMA-AFC-AFG-AFOrbitalandSpinOrderingsPhysics:SpinOrbitalLatticeDoubleexchangeSuper-exchangeCompressionLessconductivityElectric-Field-inducedOrbitalSwitchingK.Hatsuda,APL83,3329(2023).LatticeSpinChargeOrbitalElectronicStructuresofCa2-xSrxRuO4EnergyDownspinUpspinEFO-2pO-2pt2gt2gegeg3-foldCa2-xSrxRuO4

:IsovalentsubstitutionRotationRotationRotation++TiltingTilting+CompressionAFMottInsulatorNearlyFMMetalS.Nakatsuji,etal.,PRLO.Friedt,etal.,PRBIssues:(1)Howtounderstandthecomplicatedphasediagram.(2)What’stheruleoforbital.EffectsofStructureDistortionsZ.Fang&K.Terakura,PRB64,R20509(2023)RotationxyorbitalVHSFMTiltingyz,zxnestingAFOccupationsandMagnetizationsZ.Fangetal.PRB(2023).OrbitalPhaseDiagramofCa2-xSrxRuO4CaSrDopingx0.0EEfxyyz,zxEEfxyyz,zxEEfxyyz,zxxyxyferro-orbitalorderingAF,S=1fromyz,zxFM,S=1/2fromxyItinerantyz,zxwithsmallSNMstateWithVHSfromxy1.J.H.Jung,

Z.Fang,et.al.,PRL

91,056403(2023).2.Z.Fang,et.al.,PRB69,045116(2023).[110]RuO6

八面體在表面旳旋轉(zhuǎn)Sr2RuO4旳表面電子構(gòu)造LEEDSTM1.R.Matzdorf,

Z.Fang,et.al.,SCIENCE

289,746(2023).2.Z.Fang,et.al.,PRB64,R20509(2023)PDOSofvariousdopingxExp.XASCalculatedXAS90K300KOpticalconductivityExperimentsCalculationsJ.H.Jung,Z.Fang,etal.PRL(2023).FeFeMSr2FeMO6(M=Mo,W,Re)8?WhyTcissohighforM=Mo,Re?WhyM=WcaseisAFinsulator?EFdstatesdstatesMajorityspinMinorityspinModstateorotherpstatesFMZ.Fang,et.al.,PRB63,R180407(2023)EFdstatesdstatesMajorityspinMinorityspinModstatesorotherpstatesAFNewMechanismforSr2FeMO6and(Ga1-xMnx)AsFe(t2g)SpinEFM(t2g)(M=Mo,Re