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High-pressureRHEEDstudyofthegrowthofoxidethinfilmsandheterostructuresbyusingPLDJieLi,YFChen,KChen,WPeng,PWang,HFChu,YZhang,andDongNingZhengOutlines:•PrinciplesofRHEED–A gate to the atomic‐scale control of the surface & interface；–The state of art film growth with RHEED‐PLD systems；•Whatwehavedone,andwhatwearedoing–In situ RHEED control of the growth of STO, LAO, YBCO, and LCMO epilayers–Heterostructures of LCMO(3)/MgO(2)/LCMO(2)/MgO(1)/LCMO(1)/YBCO/LAO–Other applications•SummaryAtomicallyengineeredoxideinterface•SuperconductingInterfacesBetweenInsulatingOxides(Science 317, 1196 (2007) )•Electric-fieldcontroloflocalferromagnetismusingamagnetoelectricmultiferroic(Nature. Mater 7, 478 (2008) )•High-temperatureinterfacesuperconductivitybetweenmetallicandinsulatingcopperoxides(Nature 455, 782 (2008) )•Two-dimensionalnormal-statequantumoscillationsinasuperconductingheterostructure(Nature 462, 487 (2009) )Multilayers of sharp, clear, chemically steep, atomically smooth interface with digital layer thickness are essential.PhilWillmott,PaulScherrerInstitutZuozSummerSchool,August2008GrowthmodesofthinfilmsSpecularSpot0thLaueCirclePrinciplesofRHEEDEwaldSphereCrystaltruncationrods(CTR)ShadowEdgeTransmitSpotV(kV)λ(Å)10.389100.122200.0853250.0760300.0690500.0525Surface Sensitive!Used STO(001)IntensityoscillationofthespecularreflectionOne oscillation period vs.one complete monolayerLayer‐by‐layer growth mode•Pattern–Streak position (structure)–Shape of streaks (surface morphology)–FWHM–Kikuchi lines......•Oscillation–Long time scale (layer‐by‐layer modulation)–Short time scale (pulse laser modulation)–Growth mode transition……01020304050200040006000φ0phase=1.51Intensity(a.u.)Time(s)(00)specularspotIncidentangle:1.1oLippmaa et al. , Appl. Phys. Lett., 76, 2439 (2000)homoepitaxialSrTiO3thinfilmsGrowthmodecontrol:depositionratevs.temperatureMarkHuijbenInterfaceEngineeringforOxideElectronics:Tuningelectronicpropertiesbyatomicallycontrolledgrowth,PhDthesisUniversityofTwente,Enschede,TheNetherlands(2006).:CCD5:phosphorscreen8:stainlesssteelextension13:electrongun14:shieldingChamber(Pa)Electrongun(Pa)2×10-44×10-5113.2×10-4207×10-4351.1×10-3504.5×10-3LAO (001) atvacuum& PO2=25 PaOurhigh-pressureRHEEDsystemOurRHEED:someearlyresults(in2000)TheimagewastakenbydigitalcameraSiwaferin10－4PavacuumSiwaferin28PaoxygenThepatternwascollectedbyaCCDcamera,buttherewasnomulti-frameaverageandthebeamfocuswasinabadconditionSTO：Nb(2%)onSTO(100)700°C,5Pa,1Hz3minSTO：Nb(2%)onSTO(100)700°C,5Pa,1Hz15min+4Hz8minOurRHEED:someearlyresults(in2003)2526272829303132333435363738394041140000160000180000Intensity(a.u.)Time(s)0.00.51.01.52.02.53.03.510-210-1100101102103104105106107108109Frequency(Hz)Power1Hz0.06Hz16.7pulseperlayergrowthrate=0.07nm/pls.-14000-12000-10000-8000-6000-4000-2000020000.00000.00050.00100.00150.00200.00250.00300.0035Frequency(Hz)Angle(deg)020040060080010001200140002,0004,0006,0008,00010,00012,0004004104204304404504604704804905008,0008,2008,4008,60002040608010012014090000100000110000120000130000140000150000160000170000180000190000200000210000220000230000Intensity(a.u.)Time(s)Originaldata6pointAASmoothingofosc4_B5E-4HzLowPassFilteronosc4_BYBCO/STO720oC13PaOurRHEED:someearlyresults(in2004)我们自行开发的图像采集软件VacuumannealingofLAOandSTOonsurfacemorphologyRT200°C750°CLAOSTO[100]ThehomoepitaxyofSTO0102030405004000800012000phase=1.95phase=1.51phase=1.22phase=1.121.1o1.3o0.76oIntensity(a.u.)Time(s)t3/2T0.6o010203040504000800012000φ0phase=1.51φ1phase=1.39φ2phase=1.38Intensity(a.u.)Time(s)φ3phase=1.01(00)specularspotIncidentangle:1.1oPhase t3/2/ T =1.5, out‐of‐phase Peak：completeofonefulllayerValley:halflayer010203040502000400060008000(01)phase=1.58(01)phase=1.03(00)phase=1.39Incidentangle:1.1oAzimuthalangle:φ1Intensity(a.u.)Time(s)-ThehomoepitaxyofSTO0204060801001201401600.60.81.00204060801001200.40.60.81.00204060800.40.60.81.0Time(s)f=3HzT=3.2sNormalizedIntensityI/Ion(c)(b)f=1HzT=9.7sf=5HzT=2s(a)01020304050600.60.81.0(c)(b)Time(s)(a)01020304050600.40.60.81.020PaT=5s10PaT=4sNormalizedIntensityI/Ion01020304050600.70.80.91.0~10-4PaT=2s(a)~10-4Pa,(b)10Pa,(c)20Pa850℃,5Hz(a)5Hz,(b)3Hz,(c)1Hz850℃,~10-4PaTransition from layer‐by‐layer to step flow with decreasing fand increasing Ts.ThehomoepitaxyofSTO0501001502002503007000800090001000011000ΙΙIntensity(a.u.)Time(s)Ts=710°CPO2=11Paf=1Hz0.05ML/sΙ(a)20406080100800088009600Seefig.5.10(c)Intensity(a.u.)Time(s)(b)Intervalgrowth(20s)Lasermodulation→timeconstantt0~0.2s.Themaximumlaserrepeatrateis5Hz0.00.10.20.30.40.50.60.70.00.20.40.60.81.0ExperimentaldataI=I0(1-e-t/t0)fittimeconstant:t0=0.2sNormalizedIntensityI/I0Time(s)(c)T=22sThehomoepitaxyofLAOonvicinalsubstratesRHEEDpatternsofa20°miscutLAOsubstrateat950℃in1atmO2.(a)and(b)before;(c)and(d)after.The Step‐Flowgrowth mode is favored by t