November8,2017
1
LeidenInstituteofChemistry
2017
LeidenInstituteofChemistry
LeidenUniversity
November8,2017
2
LeidenInstituteofChemistry
November8,2017
3
LeidenInstituteofChemistry
DutchSPMDay2017
Organizedby:
LeidenUniversity
IreneGroot
Secretary:JoséDijkzeul
November8,2017
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LeidenInstituteofChemistry
Program
9.00-9.25:arrival+coffee9.25-9:30:opening
9.30-10.20:invitedtalkMarkusHeyde,FritzHaberInstituteBerlin,Germany"LookingintotheStructureofGlassbyDesigningaNew2DMaterial"10.20-10.40:contributedtalkSamuelLesko,Bruker"Highresolutionelectricalcharacterizationinliquidbyconductivenanoelectrodeprobes"10.40-11.00:contributedtalkMaartenLeeuwenhoek,LeidenUniversity/TUDelft"NanofabricatedSTMdouble-tipsforprobingquantummaterials"
11.00-11.30:coffee/teabreak
11.30-11.50:contributedtalkXinDeng,LeidenUniversity"InsituobservationofPtelectrodebyelectrochemicalAFMinsulfuricacidunderpotentialcyclingconditions"11.50-12.10:contributedtalkPantelisBampoulis,TUTwente"Pressureinducedmeltingofnanoconfinedice"12.10-12.30:contributedtalkMarlouSlot,UtrechtUniversity"(Below)2D:realizingelectronicstructuresonaCu(111)surfacebyatomicmanipulation"
12.30-14.00:lunch,exhibition,postersession
14.00-14.50:invitedtalkVolkerRose,ArgonneNationalLaboratory,USA"SynchrotronX-rayScanningTunnelingMicroscopy:ANovelApproachfortheNanoscaleCharacterizationofMaterialswithChemicalandMagneticContrast"14.50-15.10:contributedtalkBayTran,RUGroningen"On-surfaceformationofcumulenebydehalogenativehomocouplingofalkenylgem-dibromides"15.10-15.30:contributedtalkLeonJacobse,LeidenUniversity"CorrelationofsurfacesiteformationtonanoislandgrowthintheelectrochemicalrougheningofPt(111)"
15.30-16.00:coffee/teabreak
16.00-16.20:contributedtalkAlexanderVolodin,KULeuven"Stressdependenceofthesuspendedgrapheneworkfunction:VacuumKelvinprobeforcemicroscopyanddensityfunctionaltheory"16.20-16.40:contributedtalkOlegKurnosikov,TUEindhoven"FunctionalizationofcleavedprobesforSTMandAFM"16.40-17.00:contributedtalkMartindeWit,LeidenUniversity"Quantifyingspin-induceddissipationusingM(R)FM"
17.00:drinkssponsoredbyBruker(“BrukerBorrel”)
November8,2017
5
LeidenInstituteofChemistry
9:30 MarkusHeyde,FritzHaberInstituteBerlin
LookingintotheStructureofGlassbyDesigningaNew2DMaterialMarkusHeyde,Fritz-Haber-InstitutderMax-Planck-Gesellschaft,Faradayweg4-6,14195
Berlin,Germany,Electronicmail:[email protected] the structure of amorphous materials used to be challenging due to thecomplexityofthismaterialclass.HereIwouldliketoreviewstructuralstudiesofbulkandtwo-dimensionalamorphoussilica, focusingontherecentdiscoveryanew2Damorphousmaterial. For the first time a clear image of an amorphous network structure has beenobtainedwhichallowedforthederivationofatomicsitesandadetailedanalysisfromrealspacecoordinatesbyusingscanningtunnelingandatomicforcemicroscopy.Iwilldiscussthebenefitsofthesemeasurementsonthenewlydevelopedthinsilicabilayerfilmsystemandconsidercomparisonsbetweentwo-dimensionalstructuresandtheirthree-dimensionalbulksilicacounterparts.Recentexperimentswhichestablish2Damorphoussilicaasacandidateinsulatingmaterialfortwo-dimensionalnanoelectronicswillalsobediscussed.Furthermore,Iwouldliketoprovideyouasneakpreviewintothelatestresultspointingtowardsanotheramorphousoxidefilmsystem.
November8,2017
6
LeidenInstituteofChemistry
10.20 SamuelLesko,Bruker
Highresolutionelectricalcharacterizationinliquidbyconductivenanoelectrodeprobes
SamuelLesko,PeterDeWolf,RakeshPoddar,andZhuangqunHuang*BrukerNanoSurfaces,112RobinHillRoad,Goleta,California,CA,93117,USA
*CorrespondingAuthor:[email protected] and catalytic researches are nowadays topics of importancewhere reactivity andelectricalpropertiesheterogeneityofmaterialsonthenanoscalehaveasignificantimpactonmacroscopic performance. The differences in structural, mechanical, electrical, and/orelectrochemicalpropertieslocallyalltogetheraccountforthisreactivityvariation.Therefore,approachescapableofsimultaneouslycapturingcorrelatedmultidimensionalinformationonthe nanoscale in liquid media are highly desire to perform in situ, in vivo, non-invasivecharacterizationduetothenaturesofthesamples.Whileclassicscanningelectrochemicalmicroscopy(SECM)usingmicro-electrodesisknownapproachforstudyinglocalelectrochemistry,itsufferschallengesonthepositioncontrolofthe tip-sample distance, which is essential for obtaining accurate electrochemicalinformation.Inaddition,thespatialresolvingpowerisgenerallylowanddifficulttoachievesub μm resolution. Likewise, standard AFM based techniques in air for electricalcharacterization such as capacitance, conductivity, surface potential cannot apply inconductiveliquidsduetostraightcurrentleakage.Furthermore,samples,suchasbiologicalorenergymaterialsareoftenhighlysoftandfragilewhichposesanothergrandchallengeforAFM-basedimagingusingclassiccontactmode.Recently,wehavedevelopedbatch-fabricated,high-qualityandrobustnanoelectrodeprobesfullyinsulatedfromsolutionexceptionmadefortipapexwhichexposesPt-coatedconductivetip ~200 nm height with diameter of ~50 nm. These probes pass > 10 hours continuouselectrochemicaltestingandfeaturetheeaseofuse.TheseprobesareusedincombinationwithPeakForceTapping(PFT)modewhereprobeissinusoidallymodulatedatoff-resonance,lowfrequency,withadefinedimagingforceaslowas20pN.Thisenablesinsitu,invivo,non-invasive,stableimagingforchallengingfragileandsoftsamples.PFTisessentiallybasedonfastforcecurveacquisitionandanalysis.ItnaturallyallowsquantitativemechanicalmappingsatnormalAFMscanrate.Combinationofhigh-qualitynanolectrodesprobeswithPFT,allowsus to simultaneously capture multidimensional information in the electrochemicalenvironmentat<100nmspatialresolution,includingtopographic,conductivity,mechanical,andelectrochemicalproperties.Inaddition,thenanoelectrodeprobebydesignalsoenablesallothernanoelectricmeasurementsinliquidasitisfullyinsulatedexceptforthetip.1,2
November8,2017
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LeidenInstituteofChemistry
This talk showcases a variety of applications examples using nanolectrodes, includingcatalysis,surfacedefectsonlamellar,patternednanostructuredelectrodes,etc.Associatedspectroscopymappingwillbeshowntoillustratepowerofsuchanapproach.SomeexamplesaboutnanoelectricmeasurementssuchasKelvinprobeandPiezoResponseinliquidarealsopresented.Thesecasesdemonstratetheversatilityandpotentialnewcapabilities throughthosenanoelectrodesthatarewellsuitedfortoday’shighly-multidisciplinaryresearch.
Figure1.Left:SEMimagesoftheprobe.TheprobeisfullyinsulatedwithonlythePt-coatedtipapexexposed.Right:Exampleofelectricalcharacterizationinliquid.Oncenter:batteryelectrodeinDMCwithcontactcurrentmapping inPeakForceTapping.On left,meshofSiliconNitridewithopeningmadeofPlatinum ismeasuredbyFrequencyModulationbasedKelvinprobemicroscopy inmilli-Qwater.References:1Nellistetal.,Nanotechnology,2017,28,095711.2Huangetal.,MicroscopyToday,2016,24,18.
November8,2017
8
LeidenInstituteofChemistry
10.40 MaartenLeeuwenhoek,LeidenUniversity/TUDelft
NanofabricatedSTMdouble-tipsforprobingquantummaterialsMaartenLeeuwenhoek1,2,RichardNorte1,KoenM.Bastiaans2,IreneBattisti2,YaroslavM.
Blanter1,JanZaanen2,MilanP.Allan2andSimonGröblacher11:KavliInstituteofNanoscience,DelftUniversityofTechnology,2628CJDelft,The
Netherlands2:LeidenInstituteofPhysics,LeidenUniversity,NielsBohrweg2,2333CALeiden,The
Netherlands
Here, we report on the design and fabrication of a new type of smart tip for ScanningTunneling Microscopy (STM). By fully integrating a metallic tip onto a silicon chip usingmodernmicro-machiningandnanofabricationtechniquesweshowthepossibilityofdevicebasedSTMtips.Contrarytotraditionaletched/grindedwiretips,thesecanbeintegratedinlithographicallydefinedelectricalandphotoniccircuits,aswellaswithmechanicalsystems.We aim at creating two-probe deviceswith a tip to tip spacing below ~50-100 nm. Suchdoubletipscouldnotonlymeasurethelocaldensityofstatesatthetwoindividualtipswithatomicresolution,butalsothecurrentsentthroughonetipandcollectedbytheother.Thiswouldallowustomeasureandmapthetwopointpropagatoroftheelectrons,providingnewinformationonthetransportofcorrelatedelectronsattheatomicscale.
November8,2017
9
LeidenInstituteofChemistry
11.30 XinDeng,LeidenUniversity
InsituobservationofPtelectrodebyelectrochemicalAFMinsulfuricacid
underpotentialcyclingconditions
XinDeng,FedericaGalli,MarcT.M.Koper
UnderstandingtheelectrochemicalbehaviorofPtatsolid/liquid interface isofsignificantimportancetothedevelopmentofefficientelectrochemicaldevices,suchasfuelcellsandwaterelectrolyzers.Inthiswork,theevolutionofthesurfacemorphologyofapolycrystallineplatinum under potential cycling condition was investigated by EC-AFM. After 50 cyclesbetween0.05-1.8Vin0.1MH2SO4,thePtsurfaceiscoarsenedandnanoparticlesofseveralnanometersappearonthesurface.Thecriticalupperandlowerpotentialfornanoparticlesformationisfoundtobe1.8and0.8V,respectively.TheinsituAFMobservationcoupledwithCV reveals the periodic disappearance and reappearance of the nanoparticles, based onwhich, the nanoparticles are attributed to be Pt nanoparticles and a model for thenanoparticles formation is proposed. While the formation of a thick oxide layer is theprerequisite,thereductionprocessisfoundtohaveastronginfluenceonPtnanoparticlesformation as well. This investigation provides the visualization of Pt surface underelectrochemical control in a large potential window, which enables a more intuitiveunderstandingofthePtredoxprocess.
November8,2017
10
LeidenInstituteofChemistry
11.50 PantelisBampoulis,TUTwente
Pressureinducedmeltingofnanoconfinedice
PantelisBampoulis,TUTwenteThestatesofaggregationofconfinedwaterarehighlyimportantandofgreatfundamentalinterestinsurfacechemistry,lifeandenvironmentalsciences.Duetolimitedexperimentalaccessacoherentunderstandingofthephasebehaviorandtheoccurringphasetransitionsof interfacial ice is still lacking. Using scanning probe techniques,we show that, at roomtemperature, ice confined between graphene and muscovite mica undergoes a phasetransition to a quasi-liquid phase at a critical applied pressure of 6GPa. The transition iscompletely reversible, that is, refreezing occurs when the applied pressure is lifted. Ourfindings form a paradigm of the classical phenomenon of regelation decoupled fromenvironmentalthermaleffects.Thecriticalpressuretomelttheicecrystalsislowerathighertemperatureandthelatentheatoffusion(0.15eV/H2O)ismorethantwotimeslargerthanthecorrespondingthreedimensionalvalueatambientconditions.
November8,2017
11
LeidenInstituteofChemistry
12.10 MarlouSlot,UtrechtUniversity(Below)2D:realizingelectronicstructuresonaCu(111)surfacebyatomic
manipulation
M.R.Slot1,S.N.Kempkes2,T.S.Gardenier1,P.H.Jacobse1,G.C.P.vanMiert2,S.J.M.Zevenhuizen1,C.MoraisSmith2,D.Vanmaekelbergh1andI.Swart1
1DebyeInstituteforNanomaterialsScience,UtrechtUniversity,theNetherlands2InstituteforTheoreticalPhysics,UtrechtUniversity,theNetherlands
Geometryanddimensionalityaredecisivefactorsfortheelectronicpropertiesofmaterials.Anexample is the2-Dhoneycomb latticeofgraphene,giving rise toDiraccones inwhichchargecarriersbehaveaseffectivelymasslessparticles.Apossibleroutetocreatenovelflatstructures inacontrolledmanner isbyconfiningthesurfacestateelectronsofCu(111)byaccuratepositioningof adsorbedCOmolecules [1]. Employing this strategy,we show therealizationofaLieblattice[2]:a2Dsquare-depletedlattice,whichischaracterizedbyabandstructure featuring Dirac cones intersected by a flat band. Using scanning tunnellingmicroscopy, spectroscopy and wavefunction mapping, we confirm the predictedcharacteristicelectronicstructureoftheLieblattice.Athigherenergies,wefindstatesthatoriginatefromtheartificialp-orbitalsoftheelectroniclattice.Moreover,wemovebeyondthe well-studied integer dimensions. Fractional dimensions could open a new range ofpossibilitiesforelectronicnanosystems.Here,werealizeandcharacterizeaSierpińskitrianglefractalwithdimension1.58.Wefindthat the fractalityof thisquantumfractal isnotonlyreflectedinthegeometryandenergylevels,butalsointhewavefunctions,whicharefractalthemselves. The experimental findings were reproduced by muffin-tin and tight-bindingcalculations.1.K.K.Gomesetal.,Nature483,306–310(2012)2.M.R.Slotetal.,NaturePhysics13,672-676(2017)
November8,2017
12
LeidenInstituteofChemistry
14.00 VolkerRose,ArgonneNationalLaboratory,USA
SynchrotronX-rayScanningTunnelingMicroscopy:ANovelApproachfortheNanoscaleCharacterizationofMaterialswith
ChemicalandMagneticContrast
VolkerRoseX-rayScienceDivision&CenterforNanoscaleMaterials
ArgonneNationalLaboratory9700SouthCassAvenue
Argonne,IL60439-4800,USAAdj.Professor,Physics&AstronomyDepartment
OhioUniversity,Athens,OH45701,USA
The real-space observation of chemistry and magnetic structure using scanning probemicroscopy(SPM)methodsorsynchrotron-basedx-raymicroscopy(XM)continuestohaveatremendous impactonourunderstandingoffunctionalmaterials.However,althoughSPMmethodsprovidehighspatialresolution,theytypicallylackdirectchemicalcontrastandtheabilitytoquantifymagneticmoments.Ontheotherhand,XMcanprovidechemicalaswellasmagnetic sensitivity, but the spatial resolution is inferior. In order to overcome theselimitations, various groups have developed a new technique that combines synchrotronradiationwiththehighspatialresolutionofscanningtunnelingmicroscopy(STM).Thegoalistocombinethespinsensitivityandchemicalcontrastofsynchrotronx-rayswiththelocalityofSTM.Recently,substantialprogresswasmadeonArgonne’ssynchrotronx-rayscanningtunnelingmicroscopy (SX-STM) project. In particular, we demonstrated the power of SX-STM forelemental characterization and topography of individual Ni and Co nano-islands at 2 nmlateral resolutionwith single atomheight sensitivity [1,2], tested newprobe tip conceptsbasedoncarbonnanotubes[3]andmultilayertips[4],anddemonstratedx-rayimagingofnanoscalemagneticdomainsofanironthin-filmbyx-raymagneticcirculardichroism(XMCD)contrast[5].Furthersubstantialadvancesareexpectedusingthenewlowtemperature(LT)SX-STM system, which has been developed over the last 3 years and is currently undercommissioning.Tofullyexploitthespecialcapabilitiesofthenewmicroscope,XTIP,adedicatedbeamlineforSX-STMisunderconstructionattheAdvancedPhotonSource.Tomeetthescientificobjectiveofthenanoscienceandnanomagnetismcommunitiesmosteffectively,wearegoingtobuildasoftx-raybeamlinewithfullpolarizationcontroloperatingoverthe500-2000eVenergy
November8,2017
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LeidenInstituteofChemistry
range. The dedicated XTIP beamline will provide researchers access to a one-of-a-kindinstrument. Among the potential breakthroughs are “designer” materials created fromcontrolled assemblies of atoms and molecules, and the emergence of entirely newphenomenainchemistryandphysics.Thisworkwas fundedbytheOfficeofScienceEarlyCareerResearchProgramthroughtheDivisionofScientificUserFacilities,OfficeofBasicEnergySciencesoftheU.S.DepartmentofEnergythroughGrantSC70705.ThisworkwasperformedattheAdvancedPhotonSourceandtheCenterforNanoscaleMaterials,aU.S.DepartmentofEnergyOfficeofScienceUserFacilityunderContractNo.DE-AC02-06CH11357.References:[1] N.Shiratoetal.,NanoLetters14,6499(2014).[2] H.Kerselletal.,Appl.Phys.Lett.,inprint(2017).[3] H.Yanetal.,J.Nanomaterials2015,492657(2015).[4] M.Cummingsetal.,J.Appl.Phys.121,015305(2017).[5] A.DiLulloetal.,J.SynchrotronRad.23,574(2016).
November8,2017
14
LeidenInstituteofChemistry
14.50 BayTran,RUGroningen
On-surfaceformationofcumulenebydehalogenativehomocouplingofalkenylgem-dibromides
B.Tran,1Q.Sun,2L.Cai,2H.Ma,2X.Yu,2C.Yuan,2M.Stöhr,1andW.Xu21ZernikeInstituteforAdvancedMaterials,UniversityofGroningen,Groningen,Netherlands
2InterdisciplinaryMaterialsResearchCenter,TongjiUniversity,Shanghai,China
Recently,on-surfacesynthesisbasedontheuseofcovalentlinkinghasofferedanexcellentplatform to construct novel 1D and 2D carbon-based materials. This new approach hasreceivedconstantlyincreasingscientificattentionbecauseofitsadvantagescomparedtoitscounterpart solution-based synthesis for building durable, controllable nanostructures forfutureelectronicdevices.ThemostfrequentlyusedreactionisUllmann-typecouplingwhichinvolvesthethermallyinduceddehalogenationofpre-definedC-Xgroups(X=halogenatom)fortheformationofC-Cbonds.Sofar,allemployedhalideprecursorshaveonlyonehalogenattached to a carbon atom. Therefore, to extend our fundamental understandings of on-surfaceC−Ccouplingreactionsitisparticularinteresttostudytheeffectofintroducingmorethan one halogen atom to a carbon atom with the aim of producing multiple unpairedelectrons.In this work, we successfully fabricated cumulene products on a Au(111) surface viadehalogenativehomocoupling reactionsby introducinganalkenylgem-dibromide [1].Thereactionproductsandpathwayswereunambiguouslycharacterizedbythecombinationofhigh-resolution scanning tunneling microscopy (STM) and non-contact atomic forcemicroscopy(nc-AFM)measurementstogetherwithstate-of-the-artdensityfunctionaltheory(DFT) calculations. This study further supplements the database of on-surface synthesisstrategies,andimportantly,itprovidesafacilemannerforincorporationofmorecomplicatedcarbonscaffoldingsintosurfacenanostructures.[1]Q.Sun,B.Tran,etal.,Angew.Chem.Int.Ed.56,12165–12169(2017).
November8,2017
15
LeidenInstituteofChemistry
15.10 LeonJacobse,LeidenUniversity
CorrelationofsurfacesiteformationtonanoislandgrowthintheelectrochemicalrougheningofPt(111)
LeonJacobse1,Yi-FanHuang1,MarcT.M.Koper1,andMarcelJ.Rost21LeidenInstituteofChemistry,LeidenUniversity,Leiden,TheNetherlands
2Huygens-KamerlinghOnnesLaboratory,LeidenUniversity,Leiden,TheNetherlandsPlatinum plays a central role in a wide variety of electrochemical devices. Electrodedegradation, especially under oxidizing conditions, forms an important barrier for thewidespreadapplicationof suchdevices.Although it isknownthat repeatedoxidationandreductionofplatinumelectrodesresultsinirreversiblesurfacestructurechanges,overthirtyyearsofresearchdidnotyetyieldtoaconclusivedescriptionofthisprocessontheatomiclevel;notevenforwell-definedsinglecrystalsurfaces.Using a special EC-STM, which is capable of measuring the electrochemical signalssimultaneously during imaging in operando, we directly correlate, for the first time, theevolution of the electrochemical (hydrogen desorption) signal of Pt(111) to the observedroughening of the surface. In the later stages, we find a strong correlation between theevolutionoftheroughnessandtheabsorptionpeaksclearlyindicatingthateachcreatedstepcontributesequallystrongtotheadsorptionsignalaswellastotheroughness.However,andfully surprising, in the early stages step edges are created that do not contribute to theelectrochemicalsignal.TheseresultspresentnotonlyanimportantstepforwardinunderstandingtheatomicscaleprocessoftheelectrochemicalrougheningofPt(111),butalsoprovidevaluableinsightinthedegradationofindustriallyrelevantplatinumnanoparticles,asalargepartoftheirsurfaceisnaturallycomposedoutof{111}planes.
November8,2017
16
LeidenInstituteofChemistry
16.00 AlexanderVolodin,KULeuven
Stressdependenceofthesuspendedgrapheneworkfunction:VacuumKelvinprobeforcemicroscopyanddensityfunctionaltheory
A.Volodin,1C.VanHaesendonck,1O.Leenaerts,2B.Partoens,2andF.M.Peeters2
1KULeuven,AfdelingVaste-stoffysicaenMagnetisme,Celestijnenlaan200D,BE-3001
Leuven,Belgium2UniversiteitAntwerpen,DepartementFysica,Groenenborgerlaan171,BE-2020Antwerpen,
BelgiumWe report on work function measurements on graphene, which is exfoliated over apredefined array of wells in silicon oxide, by Kelvin probe forcemicroscopy operating invacuum. The obtained graphene sealed microchambers can support large pressuredifferences, providing controllable stretching of the nearly impermeable graphenemembranes.These measurements allow detecting variations of the work function induced by themechanicalstressesinthesuspendedgraphenewheretheworkfunctionvarieslinearlywiththestrainandchangesby62±2meVfor1percentofstrain.Ourrelatedabinitiocalculationsresultinworkfunctionvariationlargerbyafactorof1.4thantheexperimentalvalue.The limiteddiscrepancybetweentheoryandexperimentcanbeaccountedforbyachargetransferfromtheunstrainedtothestrainedgrapheneregions.
A.Volodinetal.,Appl.Phys.Lett.110,193101(2017)
November8,2017
17
LeidenInstituteofChemistry
16.20OlegKurnosikov,TUEindhoven
FunctionalizationofcleavedprobesforSTMandAFM
O.Kurnosikov,H.T.Ciftci,B.KoopmansAnalternativetypeofprobesforSTMortuningfork-basedAFMisproposed[1].Insteadofusingtraditionalneedle-liketipsmadefromametallicwire,weuseasharpedgeofacleavedinsulatingsubstratewhichinitiallywascoveredbyathinlayerofconductingmaterial.Thesharptipisformedattheintersectionoftwocleavinglines.TestingthecleavedtipsinSTMandAFMrevealstheresolutiondowntoatomicscale,thesameasforconvenientSTM/AFMtips.However,withourapproach,theplanarsubstratesfortipfabricationareverysuitableforaverysimpleandflexiblefunctionalizationoftheSTMandAFMtips,forexamplebyusingthe cleavable substrates with magnetic, superconducting or other specific layers for tipfabrication. Moreover, profiting from Electron Beam or Focused Ion Beam Lithography(EBL/FIB) we also were able to tailor themetallic layer to obtain two- or multi-terminalstructuresontheprobe.Theelectriccurrentacrossamicro-ornanostructureformednearthetipendcanmodulatethetip-sampleinteractionandcanbeusedeitherforaswitchablesensingorasamplemanipulationonthenanoscale.Asanexamplewepresentaprototypeofmagnetically switchable or adaptiveMFMprobes. The current sent through a 100 nmconstrictionnearthetipendcangeneratealocalizedmagneticfieldofupto20mTwhichissufficient formagneticmanipulation. Inthesameway it isalsopossibletogenerateshortheatingpulsesforlocalmodificationofthesampleornano-printing.1.T.Siahaanetal.Nanotechnology,27,03LT01(2016)
November8,2017
18
LeidenInstituteofChemistry
16.40 MartindeWit,LeidenUniversity
Quantifyingspin-induceddissipationusingM(R)FM
MartindeWit,GesaWelker,MarcdeVoogd,JelmerWagenaar,ArthurDenHaan,TjerkOosterkamp
Magnetic Resonance ForceMicroscopy is a technique that uses a very soft cantilever tomeasuretheforcesbetweenitsmagnetictipandthespinsinasample.Typically,MagneticResonanceprotocolsareusedtomanipulatethemagnetizationofthespinensemble,therebychangingthetip-sampleinteraction.However,wehaveutilizedtheextremeforcesensitivityofourMRFMsetuptomeasurethedensityandT1timesofparamagneticspinsinthenativeoxidelayerofsilicon,withoutsendingresonantpulses.Wealsodeterminedthedensityofthefreeelectronspinsassociatedwithnitrogendefectsindiamond.Toexpandthenumberofapplicationsofthistechnique,wearecurrentlyworkingonanewMRFMsetup,nicknamedtheEasy-MRFM. Itwill enablemeasurementsona larger varietyof samples since it isnolongernecessarytointegratethesampleunderinvestigationwiththechipthatgeneratestheoscillatingB1fieldandprovidesthedetectionofthemotionoftheforcesensor.
November8,2017
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LeidenInstituteofChemistry
PosterAbstracts
November8,2017
20
LeidenInstituteofChemistry
Poster1
ImagingPulsedLaserDepositionoxidegrowthbyin-situAtomicForce
Microscopy
W.A.Wessels,T.R.J.Bollmann*,D.Post,G.Koster,andG.RijndersUniversityofTwente,InorganicMaterialsScience,MESA+InstituteforNanotechnology,P.O.
Box217,NL-7500AEEnschede,TheNetherlands*Correspondingauthor:[email protected]
Theperovskiteoxidesarea fascinatingclassofmaterials,due to theirwealth inavailablephysical properties, such as superconductivity, ferromagnetism, ferro- and dielectricity.Control on the growth of such (ultra)thin film structures is very beneficial as it leads tounanticipatedfunctionalproperties.However, to gain deep insight in the growth process, the current in-situ diagnostic tools(RHEED,SXRD,SE)alloperateinreciprocalspacemakinginterpretationnotstraightforwardandaveragingoverlargesurfaceareas.Inthisposter,wepresentthedevelopmentofasurfaceprobemicroscopy(SPM)techniquewithwhichweenablelocaltopographymeasurementsofthethinoxidefilmgrowthfrontinreal-spaceandatthenanometerscale.Wepresenttheconcept,specifications,designandperformanceofouratomicforcemicroscope(AFM)inapulsedlaserdeposition(PLD)vacuumsetup. The demonstrated performance on a typical perovskite oxide surfaces is of greatimportancenotonlyforthethinfilmoxidecommunity,butalsotowardsabroaderaudienceasitenablesmanymorefutureapplicationsformonitoringgrowthinprocessconditions.
November8,2017
21
LeidenInstituteofChemistry
Poster2
PoorelectronicscreeninginlightlydopedMottinsulatorsobservedwithSTM
IreneBattistietal.,LeidenUniversity
The effectiveMott gapmeasured by scanning tunnelingmicroscopy in the lightly dopediridate (Sr1-xLax)2IrO4 differs greatly from values reported by photoemission and opticalexperiments.Here,weshowthatthisisaconsequenceofthepoorelectronicscreeningofthetip-inducedelectricfield,aneffectwellknownforsemiconductorsandcalledtip-inducedbandbending(TIBB).WedevelopamodelabletoretrievetheintrinsicMottgapfordopingconcentrationsx<4%,leadingtoavaluewhichisinroughagreementwithotherexperiments.Atdopingx≈5%we furtherobservecircular features in theconductance layers, indicatinghigherdensityof freecarriersandpresenceofa small concentrationofdonoratoms.Weillustrate the importance of considering the presence of TIBB in STM experiments oncorrelated-electron systems and discuss the similarities and differences between STMmeasurementsonsemiconductorsandlightlydopedMottinsulators.
November8,2017
22
LeidenInstituteofChemistry
Poster3
Localcontrolofatomicvacanciestocreateartificialmaterials
F.E.Kalff*1,J.Girovsky1,D.CoffeyBlanco1,J.L.Lado2,E.Fahrenfort1,J.W.vanDam1,L.J.J.M.
Peters1,P.Schmitteckert4,F.Evers5,J.Fernández-Rossier2,3andA.F.Otte1
1DepartmentofQuantumNanoscience,DelftUniversityofTechnology,,Delft,TheNetherlands
2QuantaLab,InternationalIberianNanotechnologyLaboratory(INL),Braga,Portugal.3DepartamentodeFísicaAplicada,UniversidaddeAlicante,Alicante,Spain
4TheoretischePhysik,UniversitätWürzburg,Germany5TheoretischePhysik,UniversitätRegensburg,Germany
Large-scalemanipulation bymeans of scanning tunnelingmicroscopy (STM) of individualvacanciesinachlorinemonolayeronCu(100)isusedtoconstructone-andtwo-dimensionalstructuresofcoupledvacancies[1]invariousdensitiesandsizes,inordertoinvestigatetheirelectronicandspectroscopicproperties.Local scanning tunneling spectroscopy (STS) measurements reveal the emergence ofquasiparticlebands,evidencedbystandingBlochwaves,wherethenumberofnodesdependsontheenergyandthelatticestructure.Thissignifiesthatchangingthelatticepropertiesisawayoftuningthequasiparticledispersion,whichleadstodifferenteffectiveelectronmasses.Theexperimentaldatacanbeunderstoodintermsofatight-bindingmodelcombinedwithanadditionalbroadeningtermthatallowsanestimationofthecouplingtotheunderlyingsubstrate[2].1.Drostetal.,NaturePhysics13,668–671(2017)2.Girovskyetal.,SciPostPhys.2,020(2017)
November8,2017
23
LeidenInstituteofChemistry
Poster4
SurfaceStructureDependentPhysisorptionofCO2
S.V.Auras1,R.G.Farber2,R.vanLent1,3,R.Spierenburg1,D.Bashlakov4,D.Killelea2,L.B.F.Juurlink1
1LeidenInstituteofChemistry,LeidenUniversity,
2LoyolaUniversityChicago,3DutchInstituteforFundamentalEnergyResearch,4ILTPE,NationalAcademyofSciencesofUkraine
Thereactivityofcommercialmetalcatalystsisoftensignificantlyinfluencedbythepresenceofdefects,suchassteps,kinks,oradatomsonthecatalyticsurface.[1,2]Correspondingly,thesticking of CO2, a crucial step e.g. in methanol synthesis, is expected to be structuredependent.InthisprocessCO2isgenerallypredictedtobetrappedandreactasamolecularlybound species.[3] On bare metal surfaces, the adsorption of CO2 is considered to bedependentontheworkfunction,whichdecreaseswiththeintroductionofdefects.[4]Ourcurvedcrystalapproachallowsustomodeltheinfluenceofsuchdefectsinacontrolledandsystematicmanner.[5]InthisstudyweemployacurvedPtcrystalswith(111)attheapexandgraduallyincreasingstepdensities,rangingfrom<1/μmto>1/nm.ThetwosidesofthecrystalfeatureA-andB-typestepsrespectively.WeexaminethestickingofCO2bymassspectrometryandscanningtunnelingmicroscopy.LowdosesofCO2atvaryingtemperaturesgiveusauniqueinsightintotheadsorptionandstructuralorganizationofCO2atwideterracesaswellashighlysteppedsurfaces.[1]K.Honkala,A.Hellman,I.Remediakis,etal.,Science2005,307,555.[2]L.Vattuone,L.Savio,M.Rocca,Surf.Sci.Rep.2008,63,101.[3]M.Behrensetal.,Science2012,336,893.[4]U.Burghaus,Prog.Surf.Sci.2014,89,161.[5]A.J.Walshetal.,J.Vac.Sci.&Technol.A2017,35,03E102;[5]J.Janlamooletal,Molecules2014,19,10845;[5]C.Hahnetal.,J.Chem.Phys.2012,136,114201.
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LeidenInstituteofChemistry
Poster5
MimickinganAtomically-thin'VacuumSpacer'toMeasuretheHamaker
ConstantbetweenGrapheneOxideandSilica
LianyongChuetal.,TUDelft
Innanoscience,controloftheseparationbetweensurfaces,withsub-nmaccuracy,isoftenimportant.Forinstance,whenstudyingVanderWaals(VdW)forces1orcreatingnanogapsformoleculedetectionand separation2-4.Atnanometre-scale, 1Dor3D spacers, suchasnanotubesandnano-particles,aresusceptibletodeformation5.A2Dspacerisexpectedtoyieldamoreaccuratelydefinedseparation,owingtothehighatomdensityandstrengthinplanardirection.Herein,atomically thin2Dgrapheneoxide (GO)wasusedasnanometre-scale spacerwith sub-nmaccuracy, to study theVdW interaction.However, using such aphysicalspacerintroducesadditionalinteractions,obscuringtheinteractionsofinterest.Wedemonstratehowthesecontributionscanbeeliminatedbyeffectivelymimicingtheuseofa‘vacuumspacer’. In thisway,weobtain theeffectiveHamaker constantbetweenGOandsilica.1.Geim,A.K.;Grigorieva,I.V.,VanderWaalsheterostructures.Nature2013,499,419-425.2.Ward,D.R.;Grady,N.K.;Levin,C.S.;Halas,N. J.;Wu,Y.;Nordlander,P.;Natelson,D.,Electromigrated nanoscale gaps for surface-enhanced Raman spectroscopy. Nano letters2007,7,1396-1400.3.Lim,D.-K.;Jeon,K.-S.;Kim,H.M.;Nam,J.-M.;Suh,Y.D.,Nanogap-engineerableRaman-activenanodumbbellsforsingle-moleculedetection.Naturematerials2010,9,60-67.4.Li,H.;Song,Z.;Zhang,X.;Huang,Y.;Li,S.;Mao,Y.;Ploehn,H.J.;Bao,Y.;Yu,M.,Ultrathin,molecular-sieving graphene oxide membranes for selective hydrogen separation. Science2013,342,95-98.5. Sun, J.; He, L.; Lo, Y.-C.; Xu, T.; Bi, H.; Sun, L.; Zhang, Z.; Mao, S. X.; Li, J., Liquid-likepseudoelasticityofsub-10-nmcrystallinesilverparticles.Naturematerials2014,13,1007-1012.
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LeidenInstituteofChemistry
Poster6ExperimentalrealizationandcharacterizationofanelectronicLieblattice
ThomasS.Gardenier1,MarlouR.Slot1,PeterH.Jacobse1,GuidoC.P.vanMiert2,SanderN.Kempkes2,StephanJ.M.Zevenhuizen1,CristianeMoraisSmith2,DanielVanmaekelbergh1
andIngmarSwart11DebyeInstituteforNanomaterialsScience,Utrecht,theNetherlands
2InstituteforTheoreticalPhysics,Utrecht,theNetherlandsE-mail:[email protected]
Novel two-dimensional materials with promising electronic band structures can beengineered by tailoring their lattice geometries. The honeycomb lattice of graphene, forinstance, gives rise toDirac cones inwhich charge carriersbehaveaseffectivelymasslessparticles.Thesquare-depletedgeometryofaLieblatticealsogivesrisetolinearlydispersingbands,similartographene,withaflatbandintersectingtheDiraccones.WhereasopticalandphotonicLieblatticeshavebeenstudiedexperimentally[1,2],anelectronicLieblatticehadnotbeenrealizedsofar.WereportontherealizationofanelectronicLieblatticeusingastrategysimilartothemethodemployed for creating artificial graphene [3]: carbonmonoxidemolecules onCu(111) arepositionedintoananti-latticebylateralmanipulationusinganSTMtip,confiningthecoppersurfacestateelectronsintothedesiredlattice.ThecharacteristicelectronicstructureoftheLieb lattice,assimulatedusingamuffin-tinandtight-bindingapproach,wasconfirmedbyscanning tunneling spectroscopy and wave-function mapping. Moreover, second-orderelectronicpatternswereobservedathigherenergies[4].TheCu(111)/CO system formsa versatilemodel system,which allowsone to studynovellattice geometries and to tune parameters that cannot be accessed in real solid-statematerials. The scanning tunnelling microscope facilitates the realization as well as thestructuralandelectroniccharacterizationofthelattice,pavingthewayforthedesignoftrulynoveltwo-dimensionalmaterials.References[1]D.Guzmán-Silvaetal.,NewJ.Phys.16,063061(2014)[2]S.Taieetal.,ScienceAdv.1,1500854(2015)[3]K.K.Gomesetal.,Nature483,306–310(2012)[4]M.R.Slot,T.S.Gardenieretal.,NaturePhysics13(2017)
November8,2017
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LeidenInstituteofChemistry
Poster7
ForensicApplicationofAtomicForceMicroscopyforAge
DeterminationofBloodstains
ThreesSmijs(NFI),AmuHosseinzoi(NFI)andFedericaGalli(LU)
Forensic determination of the age of a bloodstain with little temporal error can provideimportantinformationinjudicialinquiry.Atomicforcemicroscopycouldprovideestimationsforbloodstainagesbasedontemporalchangesintheelasticityofredbloodcells(RBCs).Thistechnology enables RBC nano-indentations with the tip of a cantilever resulting in forcemeasurements and high resolution mapping of nanomechanical cell properties like theYoung’smodulusofelasticity.ThisstudyappliedatomicforcemicroscopytoinvestigatetheelasticityofrandomlyselectedRBCs from the peripheral zone of 4- to 8-day-old bloodstains (controlled laboratoryconditions). Special attention was paid to the condition of the silicon probes whencontinuously used to indent RBCs. The elasticity of 6 RBCs from a 5-day-old bloodstainappearedhomogeneousoverthecellwithameanYoung’smodulusof1.6±0.4GPa.Dataspreadingwasforonly6.5%causedbythechoiceoftheRBC.Uponageingofabloodstain,4to8days,asignificantageeffectwasobservedinRBCelasticity(4days:0.8±0.1GPa;5days:1.7±0.9GPa;6days:2.3±0.6Gpa;7days:4.5±0.6GPa;8days:6.0±1.8GPa;probespringconstants25.16-67.48N/m).Thespreadingbetweenthedata(4bloodstains;3RBCs/stain)enabledabloodstainagedeterminationwitha24hprecisiononlyfor6-to7-day-oldstains.Inothercasesa48htemporalaccuracywasobtained.Theconditionofthesilicontipwasregularlycheckedusingscanningelectronmicroscopyandan increasingbluntnessnoticedafter4to6cellindentations.Acorrectionfactorfortheincreaseintipradiuswasthereforeappliedfordataprocessing.Particularlyforcrimesceneinvestigationsamorerobusttipisrequiredtherebyincreasingbothprecisionandaccuracyoftheelasticitydata.
November8,2017
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LeidenInstituteofChemistry
Poster8
NaClclustersgrownontopologicalinsulatorBi2Te3investigatedbyscanning
probemicroscopy
Asteriona-MariaNetsoua*,UmamaheshThupakulaa,AlexanderVolodina,AleksandrSeliverstova,TaishiChenb,FengqiSongc,andChrisVanHaesendoncka
a)Solid-StatePhysicsandMagnetismSection,KULeuven,BE-3001Leuven,Belgiumb)MaxPlanckInstituteforChemicalPhysicsofSolids,D-01187Dresden,Germany
c)NationalLaboratoryofSolidStateMicrostructures,CollaborativeInnovationCenterofAdvancedMicrostructures,andDepartmentofPhysics,NanjingUniversity,Nanjing210093,
China*[email protected]
Surfacepropertiesandtheirmodificationsoftopologicalinsulators(TIs)holdgreatpromisefordevelopinghigh-performanceelectronicsandapplicationsinquantumcomputing.Here,we choose to deposit nanometer sized atomic clusters of sodium chloride (NaCl) on thebismuth telluride (Bi2Te3) TI. The growth and electronic properties of different size NaClclusters on the Bi2Te3 were probed by means of scanning tunneling microscopy andspectroscopyunder lowtemperatureandultra-highvacuumconditions.WeobservedthatthedepositionofNaClonBi2Te3surfacesatroomtemperatureresults intheformationofNaClclusters,wheretheclustersizecanbecontrolledviathedepositiontime.Ourfindingsshow that the NaCl clusters alter the electronic properties of the TI surface of Bi2Te3 byinducingn-typedoping.CombiningtheactiveandpromisingareasofTImaterialsandclusters,ourstudymayofferanewmethodforlocaltuningofthetopologicalpropertiesandmaypavethewaytothefabricationofnanostructuredTImaterials.
November8,2017
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LeidenInstituteofChemistry
Poster9
Tuningtheelectronicandmechanicalpropertiesofgraphenebyalcoholintercalation
E.Dollekamp,P.Bampoulis,M.H.Siekman,H.J.W.Zandvliet,E.S.KooijTUTwente
Inthiswork,weuseconductiveAFMandlateralforcemicroscopytostudytheelectronicandmechanicalpropertiesofgrapheneonamicasubstrate.Byloweringtherelativehumidityandconsecutivelypurgingwithalcohol,wecreatethreedistinctintercalantregions:anunaffecteddoublewaterlayer,2Dicefractalsandalcoholintercalatedonthe2Dicefractals.Thethreeregions show a clear difference in conductivity and friction. The graphene on the 2D icefractalsshowsahighconductivityandfriction;thegrapheneonthedoublewaterlayershowsamediumconductivityandfriction;andthegrapheneonthealcoholshowsalowconductivityandfriction.Thechangeinconductivityiscausedbydopingduetoapolarized2Dicelayer,which was validated with STM experiments by Bampoulis et al.[1] So, by changing theintercalantweareabletotunetheelectronicandmechanicalpropertiesofgraphene.[1]Bampoulis,P.; Siekman,M.H.;Kooij, E. S.; Lohse,D.; Zandvliet,H. J.W.;Poelsema,B.LatentHeatInducedRotationLimitedAggregationin2DIceNanocrystals.J.Chem.Phys.2015,143,034702.
November8,2017
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LeidenInstituteofChemistry
Poster10
Pyridyl-functionalizedtriarylaminesself-assembledonAu(111)
LeonidSolianyk1,JuanCarlosMoreno-López1,JunLi1,StefanoGottardi1,MihaelaEnache1,UteMeinhardt2,MilanKivala2,MeikeStöhr1
1ZernikeInstituteforAdvancedMaterials,UniversityofGroningen,TheNetherlands2DepartmentofChemistryandPharmacy,UniversityofErlangen-Nürnberg,Germany
e-mail:[email protected]
Theengineeringofmolecularnanostructuresonwell-definedinorganicsurfacesisconsideredtobeessential forthedevelopmentof futurenanoelectronicdevices. Inordertobuildupnanostructureswith atomic precision, ultimate control over theunderlying interactions isneeded.In our work, we investigated the self-assembly of pyridyl-functionalized triarylamines onAu(111)byscanningtunnelingmicroscopy(STM),X-rayphotoelectronspectroscopy(XPS)andlowenergyelectrondiffraction(LEED).ForthedepositionofsubmonolayercoverageontoAu(111)heldatroomtemperature,aclose-packedphasewasobservedtoco-existwithtwostructurallydifferenthexagonalnanoporousnetworks.Theclose-packedphaseisstabilizedby hydrogen bonding while the nanoporous networks are held together by metal-ligandinteractionswithnative gold atoms. Thermal annealing at 180°C resulted in theexclusiveformationoftheAu-coordinatedhexagonalnanoporousnetworkwiththelargerporesize.BasedontheSTMandLEEDdata,thestructuralmodelscouldbepreciselydeterminedandwiththehelpof theadditionalXPSdata, the intermolecularaswellasmolecule-substrateinteractionswereunraveled.
November8,2017
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LeidenInstituteofChemistry
Poster11
Exploringthepotentialofgraphenenanoribbonsasmolecularelectronicjunctions
MarkJ.J.Mangnus,PeterH.Jacobse&IngmarSwart
UtrechtUniversity
Recent developments in the field of on-surface chemistry have facilitated bottom-upfabricationofdefect-freegraphenenanoribbons(GNRs).1Stateoftheartscanningtunnellingmicroscopy(STM)techniqueshavehighlightedthepossibilityofformingamolecularjunctionbetweenametallicsubstrateandtheSTMtip2,3.Tocounteractthestrongelectroniccouplingto themetal surface,wedevelopedanovel techniquewherewe introduced intercalatinglayersofNaCl,allowingustomeasuretheelectronicconductancethroughsingleribbonsasafunctionofbiasvoltageandjunctionlength.4ThisworkisabigsteptowardstheapplicationofGNRsinmolecularelectronics.1.Cai,J.etal.Atomicallyprecisebottom-upfabricationofgraphenenanoribbons.Nature466,470–473(2010).2. Koch,M., Ample, F., Joachim, C.&Grill, L. Voltage-dependent conductance of a singlegraphenenanoribbon.Nat.Nanotechnol.7,713–717(2012).3.Jacobse,P.H.etal.Electroniccomponentsembeddedinasinglegraphenenanoribbon.Nat.Commun.8,119(2017).4.Wang,S.etal.Giantedgestatesplittingatatomicallyprecisegraphenezigzagedges.Nat.Commun.7,11507(2016).
November8,2017
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LeidenInstituteofChemistry
Poster12
UniversalityofpseudogapandemergentorderinlightlydopedMottinsulators
KoenMBastiaans(1),IreneBattisti(1),VitalyFedoseev(1),AlbertodelaTorre(2,3),NikosIliopoulos(1),AnnaTamai(2),EmilyCHunter(4),RobinSPerry(5),JanZaanen(1),Felix
Baumberger(2,6),MilanPAllan(1)(1)LeidenUniversity,(2)UniversityofGeneva,(3)CaliforniaInstituteofTechnology,(4)
UniversityofEdinburgh,(5)UniversityCollegeLondon,(6)PaulScherrerInstituteHigh temperature superconductivity as it manifests in the cuprates was for long timesuspectedtobestronglyrelatedtothecopperoxidelayers,andthereforespecifictoonlythisfamilyofmaterials.Here,weinvestigatetheiridate(Sr1-xLax)2IrO4,belongingtoanewclassofquasi-2DeffectiveMottinsulators[1],whichwehaveshowntoexhibitphenomenastrikinglysimilartothecuprates[2-4].Weusespectroscopic-imagingscanningtunnelingmicroscopytovisualize the electronic structure at different doping concentrations. We measure fullygappedspectraatlowdopingconcentrations(x<4%)evenatthepreciselocationofdopantatomsthatarevisibleinthetopograph.ThisisevidenceforanimpuritybandMotttransitionoftheextracarriers,andthattheyaremoredeeplytrappedthaninthecuprates.Onlyatacertain doping threshold, the gap collapses revealing a pseudo gap and complex chargearrangements.[1]Kim,B.J.,etal.PRL101.7(2008):076402.[2]Kim,Y.K.,etal.NaturePhysics12.1(2016):37-41.[3]DeLaTorre,A.,etal.PRL115.17(2015):176402.[4]Battisti,I.,Bastiaans,K.M.,etal.NaturePhysics13.1(2017):21-25
November8,2017
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LeidenInstituteofChemistry
Poster13
Sensingthenon-collinearmagneticstructurebycombiningmagneticexchangeandspin-polarizedimaging
N.Hauptmann1,T.Hung1,J.Gerritsen1,M.Dupé2,D.Wegner1,B.Dupé2,A.A.Khajetoorians1
1RadboudUniversity,InstituteforMoleculesandMaterials(IMM),6500GLNijmegen,The
Netherlands.2InstituteofPhysics,JohannesGutenbergUniversität,55128Mainz,Germany
Non-collinear magnetic structures, as skyrmions and spin spiral for instance, have beenpredictedbeingacandidateformagnetic-basedstorageandspintronicapplications.OnekeymechanisminthesemagneticstructuresistheDzyaloshinskii-Moriyainteraction(DMI),whichemerges in the absenceof inversion symmetry and the appearanceof strong spin-orbitalcoupling.Thenon-collinearmagneticstructurealsostronglydependsonthesymmetryofthegeometric structure.For investigating non-collinear magnetic structures, spin-polarizedscanningtunnelingmicroscopy(SP-STM)haslongbeenusedtocharacterizethemagnetismofsurfaceswithatomicspatialresolution.However,theSP-STMimagesrevealnotonlythemagnetic informationbut convolutedwithelectronicand structuralproperties.ByutilizingSPEX,a new combination of spin-polarized scanning tunneling microscopy (SP-STM) andmagneticexchangeforcemicroscopy(MExFM),weobtainmoredetailedinformationonbothnanoscale skyrmions and a spin spiral system on mono-and bilayers of iron on aniridiumsurface.Weshowthatwecanresolvetheskyrmionlatticeinthemonolayerandrevealtheinfluenceofthesurfacereconstructiononthemagnetisminthebilayer.
November8,2017
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LeidenInstituteofChemistry
Poster14
AssembledferromagneticclusterchainsonanultrathinaluminiumoxidelayeronNi3Al(001)
KongyiLi,OlegKurnosikov,andBertKoopmansDepartmentofAppliedPhysics,EindhovenUniversityofTechnology,theNetherlands
Self-assembledchainsofFeclustershavebeengrownonanultrathinaluminiumoxidelayeron Ni3Al(001) by using atomic beam deposition. The non-wetting property of Fe on anoxidized surface leads to a formationofwell-defined clusters arranged in the chains. Thediameter of composed clusters can be controlled by the Fe coverage and the substratetemperature.Combiningwiththein-situtipmanipulationinascanningtunnellingmicroscope(STM),Feclustersonandoffthechainscanberemovedonebyoneorplacedintheexistingchain.Bythisway,anisolatedclusterchainisfabricated.TheSTM-tipmanipulationdoesnotonlyprovideatooltochangethegeometricalarrangementoftheclusterchainbutcanalsobeusedtomodifytheclustersinthechain.Fabricatedchainsofferromagneticclusterswoulddemonstratetheeffectsconnectingtheirferromagneticarrangementwithcurrenttransportinthefollowingin-situfour-probe-STMmeasurement.
November8,2017
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LeidenInstituteofChemistry
Poster15
Au(111)isnotasuitablesubstratetostudymodelCoMoShydrodesulfurizationcatalysts
M.K.Prabhu,A.vanVark,C.Koskamp,B.Hagedoorn,I.M.N.Groot*LeidenInstituteofChemistry
UsingScanningTunnelingMicroscopyandX-rayPhotoelectronSpectroscopy,weinvestigatedthedirect sulfidation and theoxide route to synthesizeAu(111)-supportedCoMoSmodelhydrodesulfurization (HDS) catalysts. The results demonstrate strong cobalt-substrateinteractionsinthepresenceofhydrogensulfide.DirectsulfidationrouteproducessheetsofcobaltsulfidewithvariousstoichiometrythatnotonlycorrodetheterracesofAu(111),butalsodisplacetheMoS2crystallites,especiallyathighcobalt loadings.Theresultingsurfaceroughnessandclusteringoftheactivephaseleadstopossibleblockingofactivesites.Theoxiderouteontheotherhand,showsdifferentialsulfidationofthemolybdenumandcobaltoxides.Thecobaltsulfidephaseencapsulatesthestillsulfidingmolybdenumoxideparticlesandformsa2Dcore-shell-likesystemwhichpreventsthecompletesulfidationofMoS2.ThelatticemismatchwithAu(111)favorsthereductionoftheoxideprecursorspre-sulfidation.Additionally, the strain induced by the 2D shell formation promotes the growth ofmolybdenumsulfideoverthecobaltsulfidesheetsuponextendedsulfidation.TheseeffectshavenotbeenobservedinaluminaindustrialHDScatalystsreportedsofar.WerecommendthatbyusinganoxidesubstratesuchasrutileTiO2(110),itmaybepossibletoobtainamodelsystemthatbetterrepresentstheindustrialHDScatalysts.
November8,2017
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LeidenInstituteofChemistry
Poster16
DefectDominatedChargeTransportandFermiLevelPinninginMoS2/MetalContacts
KaiSotthewes,PantelisBampoulis,RikvanBremen,QirongYao,BenePoelsemaandHarold
J.W.ZandvlietPhysicsofInterfacesandNanomaterials,MESA+InstituteforNanotechnology,Universityof
Twente,P.O.Box217,7500AEEnschede,TheNetherlands
Understanding the electronic contact between molybdenum disulfide (MoS2) and metalelectrodesisvitalfortherealizationoffutureMoS2-basedelectronicdevices.NaturalMoS2has the drawback of a high density of bothmetal and sulfur defects and impurities.Wepresent evidence that subsurfacemetal-like defectswith a density of∼1011 cm−2 inducenegative ionization of the outermost S atom complex. We investigate with high-spatial-resolution surface characterization techniques the effect of these defects on the localconductance of MoS2. Using metal nanocontacts (contact area < 6 nm2), we find thatsubsurface metal-like defects (and not S-vacancies) drastically decrease the metal/MoS2Schottkybarrierheightascomparedtothat in thepristineregions.Themagnitudeof thisdecrease depends on the contact metal. The decrease of the Schottky barrier height isattributedtostrongFermilevelpinningatthedefects.Indeed,thisisdemonstratedinthemeasured pinning factor, which is equal to ∼0.1 at defect locations and ∼0.3 at pristineregions.Ourfindingsareingoodagreementwiththetheoreticallypredictedvalues.Thesedefectsprovidelow-resistanceconductionpathsinMoS2-basednanodevicesandwillplayaprominentroleasthedevicejunctioncontactareadecreasesinsize.
November8,2017
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LeidenInstituteofChemistry
Poster17
Scanningprobemicroscopyatmagneticfieldsupto34T
L.Rossi1,J.Gerritsen2,L.Nelemans1,A.Khajetoorians2,B.Bryant1
1HighFieldMagnetLaboratory,RadboudUniversity,Nijmegen,theNetherlands2SPMgroup,InstituteforMoleculesandMaterials,RadboudUniversity,Nijmegen,the
Netherlands
Up to now, low temperature Scanning Probe Microscopy (SPM) has been limited to amagneticfieldstrengthof18T,asthemajorityofdesignshavebeenbasedonsuperconductormagnets.Forsomeexperimentalapplications–forexamplethestudyoffractalspectra ingraphenesuperlattices,theroomtemperaturequantumHalleffectandsomemetamagnetictransitions–higherfieldsarerequired.Staticfieldsofmorethan30Tcanbegeneratedindedicatedhigh-field facilitiesbywater-cooled, resistiveBittermagnetsorhybrid resistive-superconducting magnets. However, implementing SPM in a Bitter magnet is a majorchallenge,duetothehighlevelofvibrationalnoiseproducedbytheturbulentcoolingwater,inadditiontothestrongspaceconstraintsresultingfromthesmallmagnetbore.Wepresentanovel cryogenicScanningTunnellingMicroscope (STM)designed tooperateinside a water-cooled Bitter magnet, which can reach a magnetic field of 38 T. TheperformanceoftheSTMisdemonstratedthroughLandau leveltunnellingspectroscopyofgraphite,at4.2Kinmagneticfieldsupto34T.Additionallywe show thedesignof ahighly compactAtomic ForceMicroscope (AFM) foroperation at cryogenic temperatures in an extremely high magnetic field. We presentpreliminaryimagingdataonthefrustratedspinelCdCr2O4atupto30T.
November8,2017
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LeidenInstituteofChemistry
Poster18
LowEnergyElectronMicroscopyatNearAmbientPressures
AndreasThissen;SPECSSurfaceNanoAnalysisGmbH,Germany
Low-energyelectronmicroscopy(LEEM)isaspectromicroscopytechnique,whichallowsthestudy of dynamic processes at surfaces and interfaces, such as thin-film growth, surfacereactions,andphasetransitions.WiththeFELEEMP90fromSPECS,which isbasedontheinstrumentdesignbyRudolfTrompfromIBM[1,2],lateralandenergyresolutionofbelow5nmand250meV,respectively,canbeachieved.Dependingontheexcitationsourceandthesettingsontheinstrumentavarietyofdifferentimagingmodesarepossible:mirrorelectron microscopy, low energy electron diffraction (LEED), phase contrast imaging,reflectivity contrast, dark field imaging and bright field imaging, aswell as photoelectronemissionmicroscopyandspectroscopy.WehaveenhancedthetechnicalcapabilitiesoftheFE-LEEMP90towardsstudiesundernearambientconditionsbydevelopinga special samplegeometry.Thisenables theanalysisofmaterialsanddevicesundernearambientconditionsandeveninsituduringoperation.
November8,2017
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LeidenInstituteofChemistry
Poster19
Localatomicstructureandelectronicpropertiesof
graphene/Cu(111)/Al2O3substrateviascanningtunnelingmicroscopyandspectroscopy
UmamaheshThupakula†,*,Asteriona-MariaNetsou†,AleksandrSeliverstov†,Bart
Vermeulen‡,StevenBrems‡,andChrisVanHaesendonck†
†Solid-StatePhysicsandMagnetismSection,KULeuven,BE-3001Leuven,Belgium‡Imecvzw,Kapeldreef75,B-3001Leuven,FlemishBrabant,Belgium
Grapheneisasinglelayerofcarbonatomsarrangedinahexagonalhoneycombpattern.Thistwo-dimensionalhoneycombstructureofcarbonhasdrawnmuchattentioninthepastonedecadeduetoitsapplicabilitytothemostpromisingnanoelectronicsapplication.1Indeed,atomicscaleinvestigationsoftheelectronicpropertiesofgrapheneareplayingacrucialrolein understanding and tuning the exotic properties of thismaterial for its potential deviceapplications.2Inthisregard,scanningtunnelingmicroscopy(STM)andspectroscopy(STS)areunique techniques for atomic scale investigations and have been extensively used ingraphene research. Inourwork,weexplore the local atomic andelectronicpropertiesofgraphenegrownonCu(111)on sapphire substrate.We facilitate to study theatomic andelectronicstructurebehaviorofdefectfreeregionsofgraphene,grainboundaries,effectofintrinsicatomicdefects ingraphene(carbonvacancy)andpointdefects incopper.Locally,irregular moiré pattern under negative bias in the absence of grain boundary has beennoticed.PositiondependentSTSattheatomicscalehasbeenusedtocorrelatetheatomicstructureandelectronicpropertyofgrapheneonCu(111)/Al2O3.
1)A.ZurutuzaandC.Marinelli,Nat.Nanotechnol.9,730-734(2014)2)M.M.Ugeda,I.Brihuega,F.GuineaandJ.M.G.Rodriguez,Phys.Rev.Lett.104,096804(2010)
November8,2017
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LeidenInstituteofChemistry
Poster20
MagneticResonanceForceMicroscopy:ProbingSmallSpinEnsemblesin3D
GesaWelker,MartindeWit,MarcdeVoogd,JelmerWagenaar,LuciaBossoni,TjerkOosterkamp
LeidenUniversity
Magnetic Resonance ForceMicroscopy (MRFM) is a scanning probe technique for locallyprobingspin-relatedmaterialpropertieswitharesolutionof10-100nm.Theuseofmagneticresonanceallowsfordetectingspinsnotonlyonthesamplesurface,butalsointhebulk.We developed anMRFMwith a base temperature of 10mK. As a proof of principle, wedemonstrated measuring the nuclear spin-lattice relaxation time of copper at sampletemperaturesdownto42mK.Asexpected,wefindKorringa-behavior.Furthermoreweusedoursetuptodeterminetheimpurityspindensityindiamond.These are important steps on the way to investigating more complicated samples withinhomogeneous electron properties, such as iron-doped palladium, oxide interfaces,topologicalinsulatorsorstronglycorrelatedelectronsystems.
November8,2017
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LeidenInstituteofChemistry
Poster21
COoxidationonPt7onh-BN/Rh(111):Stabilityandcatalyticactivity
HamedACHOURetal.,EPFL,Switzerland
Thecomplexityofrealcatalystsintermsoftheirelectronicandgeometricstructureandtheirinteractionwiththesupportmakesfundamentalstudiesmuchsimpleronmodelcatalysts.InthiscontributionwereportonthestabilityandCOoxidationonmassselectedPt7supportedonhexagonalboronnitride(h-BN)grownonaRh(111)surface.Inthefirstcase,theideaofourexperimentsistoreducethesizeofcatalyticparticlestotheirultimatelimitinordertomakecarexhaustcatalyststhatcontain lessPt. Inthesecondcase,the inerth-BNlayer isexpectedtominimizetheeffectofthesupportonthecatalyticreactionandwillalsobeusedasanorderedarraytostabilizethesmallPtparticles.h-BNformsasinglesp2bondedatomichoneycomb layer. The misfit with the underlying Rh(111) surface leads to a stronglycorrugatedMoirépatternwith2nmdiameterareasthatarestronglyboundandsurroundedby1nmwideareasthatareonlyvan-der-Waalsboundand1Åhigher.Thelow-lyingregionsof theMoiré are known to be good trapping centers formolecules and clusters. Recentstudiesshowthath-BNpresentsagreatpotentialasfuturecatalystssupport[1].Thestabilityof thePtnanoparticles is investigated in-situbymeansofScanningTunnelingMicroscopy(STM),operatedat80K.CatalyticreactionsonthecatalystaremeasuredinsituinacustommadeUHVreactor.COoxidationhasbeenstudiedusingalternating13C16Oand18O2pulses,(atafrequencyof0.2Hz)onthePt/h-BN/Rh(111)catalystasafunctionoftemperature(300-700K).We find thatPt clustersannealed to700Kexhibit Smoluchowski ripening,above,intercalationofthePtunderh-BNtakesplace.Thestabilityisstronglyreducedunderreactionconditions,aphenomenonwhichhasalsobeenobservedforothersystemssuchasCo/h-BN/Rh(111)[2]andPt/TiO2(110)[3].TheonsettemperatureoftheCOoxidationisat500Kandtherebyhigherthanontitania[4]. Intercalatedclustersexhibitaby100K loweronsettemperatureoftheCOoxidationreactionthusimprovingthecoldstartbehavior.[1]X.Duo.etal.TheoreticalStudyoftheDepositionofPtClustersonDefectiveHexagonalBoronNitride(h-BN)Sheets:Morphologies,ElectronicStructures,andInteractionswithO.J.Phys.Chem.C.118,8868-8876(2014).[2]B.Preobrajenski.etal.ImpactofOxygenCoadsorptiononIntercalationofCobaltundertheh-BNNanomesh.NanoLett.9,2780-2787(2009).[3]S.Bonanni.etal.Reaction-InducedClusterRipeningandInitialSize-DependentReactionRatesforCOOxidationonPtn/TiO2(110)-(1Å~1).J.Am.Chem.Soc.136,8702-8707(2014).[4]S.Bonanni.etal.OvercomingtheStrongMetal−SupportInteractionState:COOxidationonTiO2(110)-SupportedPtNanoclusters.ACSCatal.1,385-389(2011).
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Exhibitors/Sponsors
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List of participants
Lastname Infix Firstname Affiliation
Achour Hamed LeidenUniversity
Ackermans Philip UniversityLeiden
Alarcon Esther Amolf
Alekseeva Yulia SPECSSurfaceandNanoanalysisGmbH
Allan Milan LeidenUniversity
Ashworth Timothy ZurichInstrumentsAG
Auras Sabine LeidenUniversity
Baarle van Gertjan LPM
Bakker Johan LeidenUniversity
Bampoulis Pantelis UniversityofTwente
Barsukoff Daan UniversityLeiden
Bastiaans Koen LeidenUniversity
Battisti Irene LeidenUniversity
Beernink Pieter PIBenelux(PhysikeInstrumente)
Benschop Tjerk LeidenUniversity
Berghaus Thomas nanoscoregmbh
Boden Dajo LeidenUniversity
Bollmann Tjeerd UniversityofTwente
Bremen van Rik UniversityofTwente
Bryant Benjamin HighFieldMagnetLaboratory
Burshille PeerA. NanoAndMoreGmbH
Bus Marcel DelftUniversityofTechnology
Castenmiller Carolien UniversityofTwente
Cho Doohee LeidenUniversity
Chu Liangyong TUDelft
CIFTCI TUUNSJ TU/e
CoffeyBlanco David TUDelft
Deng Xin LeidenUniversity
Dollekamp Edwin UniversityofTwente
Duval Jessica Scientec
Elbertse Robbie TUDelft
Emmanuel Lepleux CSInstruments
Ettema Ad ScientaOmicron
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Freeney Saoirse UtrechtUniversity
Galli Fedrica LION
Gardenier Thomas UtrechtUniversity
Gautier-Bergman Mirthe LeidenUniversity
Geluk Arjen UniversiteitLeiden
Gobeil Jeremie TUDelft
Gonzalez-Garcia Yaiza DelftUniversityofTechnology
Groot Irene LeidenInstituteofChemistry
Heerlein Holger NanoAndMoreGmbH
Heidema Pieter Hositrad
Heyde Markus FritzHaberInstitute
Hung Tzu-Chao RadboudUniversity
Jacobse Peter UtrechtUniversity
Jacobse Leon LeidenUniversity
Johann Florian OxfordInstruments,AsylumResearch
Juurlink Ludo LeidenUniversity
Kalff Floris TUDelft
Kap Özlem UniversityofTwente
Katan Allard DelftUniversityofTechnology
Koppers Remco PfeifferVacuumBenelux
Krammel Christian EindhovenUniversityofTechnology
Kurnosikov Oleg EindhovenUniversityofTechnology
Kwiecinski Wojciech UniversityofTwente
Leeuwenhoek Maarten LeidenUniversity&DelftUniversity
Lesko Samuel BrukerNanoSurfacesDivision
Li Kongyi EindhovenUniversityofTechnology
Liu Tiancheng LeidenUniversity
Mangnus Mark UtrechtUniversity
Markus Patrick Bruker
MartínezVelarte MariadelCarmen TUDelft
Netsou Asteriona-Maria KULEUVEN
Opdam Daniël Leidenuniversity
Otte Sander DelftUniversityofTechnology
Prabhu MaheshKrishna UniversityLeiden
Prokop Jacek SchaeferTechnologieGmbHRodriguezdaCruz Adonai EindhovenUniversityofTechnology
Rose Volker ArgonneNationalLaboratory
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Rossi Lisa HFML,RadboudUniversity
Ruitenbeek van Jan LeidenUniversity
Schaefer Martin SchaeferTechnologieGmbH
Schenkel Fred UniversityofLeiden
Seliverstov Aleksandr KULeuven
Sfiligoj Cristina ARCNL
Siekman Martin UniversityofTwente
Sjardin Arthur LeidenProbeMicroscopy
Slot Marlou UtrechtUniversity
Smijs Threes NFI
Solianyk Leonid UniversityofGroningen
Sotthewes Kai UniversityofTwente
Swart Ingmar UtrechtUniversity
Thupakula Umamahesh KULeuven
Tiger Carl-Johan TechnicalUniversityEindhoven
Tran van Bay UniversityofGroningen
Tuijnvander P. LeidenProbeMicroscopyb.v.
VanHaesendonck Chris KULeuven
vanRuitenbeek Jan UniversiteitLeiden
Vermeeren Pascal UniversiteitUtrecht
Vollema Victor ARCNL
Volodin Alexander KatholiekeUniversiteitLeuven
Vries de Niels EindhovenUniversityofTechnology
Weisser Ludger ParkSystemsEuropeGmbH
Welker Gesa LeidenUniversity
Wenzel Sabine UniversityLeiden
Winkel Alex JPKInstrumentsLtd
Wit de Martin LeidenUniversity,LION
Yetik Gorsel ARCNL
YILMAZ AYTAC TUDELFT
Zoetemelk Raimon STInstruments
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