correctedvcpd

Reviewers'comments:Reviewer#1(RemarkstotheAuthor):Inthiswell-writtenpaper,theauthorsreportonobservationofananisotropicelectricresponseintheMoS2/graphenevanderWaals(vdW)heterostructuresinresponsetothedirectionoftheexternalelectricfield.
Theexperimentsseemcarefullyexecutedandareaccompaniedwiththeoreticalsimulationsandmodels.
Thefinding,astheauthorsstated,revealfundamentalknowledgeofthescreeningpropertiesofvdWheterostructuresandcouldleadtonoveldeviceapplicationssuchasoptoelectronicandplasmonicdevices.
Thepresentationismoreoverofaveryhighquality.
IseenoobjectiontothepublicationoftheworkinitspresentforminNatureCommunications.
However,IdocautiontheEditorthat,asanexperimentalist,Imighthavemisseddefectsinthetheoreticalsimulation/modelling.
Reviewer#2(RemarkstotheAuthor):TheauthorspresentaninterestingstudyoftheelectricalfieldscreeningofvanderWaalsheterostructures,combiningadvancedexperimentalprobeswithfirst-principletheoryandaneasy-to-graspclassical-electrostaticapproach.
ThepaperpresentsaconvincingdemonstrationofdesignableasymmetricelectricalfieldscreeningofvanderWaalsheterostructures.
ThiscouldbeofmuchutilityinnovelelectronicdevicesbasedonvanderWaalsheterostructures.
IbelievethepapercouldtriggerseveralstudiesofelectricalfieldscreeningofvdWheterostructuresandIamthereforeinclinedtorecommendthepaperforpublications.
However,Ihavetwoconcerns:1)Whilebothindicatingasymmetricelectricalfieldscreening,thelinkbetweentheoryandexperimentisquiteweak.
Thepaperwouldbemoreconvincingiftheauthorsmadeasimplequantitativemodel(dampedoscillatormodel)showinghowthecomputedasymmetricresponsegivesrisetothevariationintheEFMphase.
Aqualitativeagreementwithsomereasonablychosenparameterswouldbesufficienttomakeacompellingcase.
2)Thechoiceofxc-functionalisunclearandmaybeinappropriate.
DRSLLisrarelyusedtodenotethevanderWaalsdensityfunctionalofDionet.
al.
vdW-DFwouldbemorestandard.
NotealsothatvdW-DFisatotalxc-energyfunctional,itisnotvdW-"corrected"GGA.
Beyondnomenclature,thestandardpartnerforthenon-localcorrelationofvdW-DFisarevPBEexchangefunctional;however,thischoicesignificantlyoverestimateinter-layerseparations.
ThetextmightbeinterpretedasiftheauthorsusedthePBEexchangefunctionalincombinationwithvdW-DFnon-localcorrelation.
However,thisisnotarecommendedchoiceandshouldbeavoidedinstudieslikethisone.
ItwouldbemoreappropriatetouseforinstancevdW-DF-cxorrev-vdW-DF2.
FormoredetailsonvdW-DF,consultROPP78,066501,2015.
Thechoiceoffunctionaliscrucialforthespecificquantitativepredictionsasinter-layerseparationscouldhavegreatbearingonthescreeningproperties.
Minorcomments:Whynotusethewordasymmetricthroughout,andnotuseanisotropic.
Thereadermightbelieveitreferstoanisotropicsusceptibility,(i.
e.
dipoleforminginthexyplane),butthatisnotthetopicofthispaper.
Someabbreviationsareundefinied,inparticularintheexperimentalsection.
MaybealsoavoidusingGasabbreivationsbothinRamanspectroscopyandfordescribingthestructure.
Yourssincerely,Dr.
KristianBerland.
1ResponsetoReviewersNCOMMS-17-33374AWethankthereviewersfortheirdetailedattentiontoourworkandtheirsupportiveandinsightfulcomments.
Wehaveconsideredeachofthecommentscarefully,andprovidepoint-by-pointresponsestothembelowinbluetext.
Relevantchangestothemanuscriptarealsowritteningreentext.
Reviewer:#1Inthiswell-writtenpaper,theauthorsreportonobservationofananisotropicelectricresponseintheMoS2/graphenevanderWaals(vdW)heterostructuresinresponsetothedirectionoftheexternalelectricfield.
Theexperimentsseemcarefullyexecutedandareaccompaniedwiththeoreticalsimulationsandmodels.
Thefinding,astheauthorsstated,revealfundamentalknowledgeofthescreeningpropertiesofvdWheterostructuresandcouldleadtonoveldeviceapplicationssuchasoptoelectronicandplasmonicdevices.
Thepresentationismoreoverofaveryhighquality.
IseenoobjectiontothepublicationoftheworkinitspresentforminNatureCommunications.
However,IdocautiontheEditorthat,asanexperimentalist,Imighthavemisseddefectsinthetheoreticalsimulation/modelling.
Reviewer:#2TheauthorspresentaninterestingstudyoftheelectricalfieldscreeningofvanderWaalsheterostructures,combiningadvancedexperimentalprobeswithfirst-principletheoryandaneasy-to-graspclassical-electrostaticapproach.
ThepaperpresentsaconvincingdemonstrationofdesignableasymmetricelectricalfieldscreeningofvanderWaalsheterostructures.
ThiscouldbeofmuchutilityinnovelelectronicdevicesbasedonvanderWaalsheterostructures.
IbelievethepapercouldtriggerseveralstudiesofelectricalfieldscreeningofvdWheterostructuresandIamthereforeinclinedtorecommendthepaperforpublications.
However,Ihavetwoconcerns:1)Whilebothindicatingasymmetricelectricalfieldscreening,thelinkbetweentheoryandexperimentisquiteweak.
Thepaperwouldbemoreconvincingiftheauthorsmadeasimplequantitativemodel(dampedoscillatormodel)showinghowthecomputedasymmetricresponsegivesrisetothevariationintheEFMphase.
Aqualitativeagreementwithsomereasonablychosenparameterswouldbesufficienttomakeacompellingcase.
ResponseWethankthereviewerforhis/hercomments.
Firstandforemost,itshouldbeemphasizedthatthequantificationofanyEFMresultsisverycomplicatedandchallenging.
Thisismainlyduetotheunknowncapacitancetermdeterminedbythetipandsamplegeometryandthelong-rangenatureofelectrostaticforce.
Theprecisecalculationoftip-samplecapacitanceisonlyachievablebynumericalmethods,andseveralcalibratedparametersadhoc(seeGomilaetal.
Nanotechnology25,255702(2014)).
Suchanalysisisbeyondthescopeofthisproject.
However,wetriedtoestablishaqualitativeagreementbetweenthesimulationandEFMexperimentusingveryroughapproximations,asrequestedbythereviewer.
2WehaveincludedanewsetofdiscussionsanddataintheSupportingInformation(1.
QualitativeanalysisontheEFMresults)whereweusereasonableparameterstostrengthenthelinkbetweentheoryandexperiments.
Wecouldestimatethebehavioroftheelectricsusceptibilityasafunctionofthebiasforoneofoursystems,3LMoS2/4LGraphene.
ItcanbeseeninFigureS2thatthereisasystematicincrementoftheelectricsusceptibilityasthebiaspointstowardsMoS2,whichfollowsthebehaviorobservedinthesimulations.
Weaddedthefollowingsentencestothemanuscript:Page7,line152:"WetriedtoqualitativelyanalyzetheEFMresultstoestimatethechangeofelectricsusceptibility()ofthe3LMoS2/4LGrapheneheterostructure(seeSupportingInformation).
ThebehaviordisplaysanincrementofwiththebiaspointingtotheMoS2surface.
"Page9,line178:"…(Fig.
2(f)andFig.
S2intheSupportingInformation)…"2)Thechoiceofxc-functionalisunclearandmaybeinppropriate.
DRSLLisrarelyusedtodenotethevanderWaalsdensityfunctionalofDionet.
al.
vdW-DFwouldbemorestandard.
NotealsothatvdW-DFisatotalxc-energyfunctional,itisnotvdW-"corrected"GGA.
Beyondnomenclature,thestandardpartnerforthenon-localcorrelationofvdW-DFisarevPBEexchangefunctional;however,thischoicesignificantlyoverestimateinter-layerseparations.
ThetextmightbeinterpretedasiftheauthorsusedthePBEexchangefunctionalincombinationwithvdW-DFnon-localcorrelation.
However,thisisnotarecommendedchoiceandshouldbeavoidedinstudieslikethisone.
ItwouldbemoreappropriatetouseforinstancevdW-DF-cxorrev-vdW-DF2.
FormoredetailsonvdW-DF,consultROPP78,066501,2015.
Thechoiceoffunctionaliscrucialforthespecificquantitativepredictionsasinter-layerseparationscouldhavegreatbearingonthescreeningproperties.
ResponseWehaveexplicitlycheckedtheeffectofdifferentvanderWaals(vdW)densityfunctional(DF)onthemagnitudeoftheinterlayerdistancebetweengrapheneandMoS2layers(dG-MoS2).
WehaveusedfourdifferentDF's,includingtheonesuggestedbythereviewer,e.
g.
BH.
WefoundminormodificationsbetweenthevdW-DFusedinourmanuscript(DRSLL)andotherswithdifferentchangesontheexchangepart.
ThemagnitudesofdG-MoS2differbyaround2%,whichalsocomparewellwithrecentvaluesreportedintheliterature1,2,3.
WealsocalculatedthechargedensityusingthesenewvdWfunctionalsandnegligiblevariationswereobserved.
ThisfullyjustifiesourchoiceofDRSLLinoursimulations.
WehaveincludedtheseresultsintheSupportingInformation(2.
InterlayerdistancebetweengrapheneandMoS2sheets),inTableS1,FigureS4,togetherwithdiscussions,comparisonwithliteratureandnewreferences.
Wehaveincludedinpage28,line502,thefollowingsentencesreferringtothisanalysis:"WehaveexplicitlycheckedtheeffectofdifferentmodificationsontheexchangepartofthevdWdensityfunctionalontheinterlayerdistancebetweengrapheneandMoS2asshowninTableS1intheSupportingInformation.
Minor3differenceswerefoundbetweenDRSLLandothervdWfunctionals,astheinterlayerdistancechangesbyaround2%.
Thisresultedinnegligiblevariationsonthechargedensity(FigureS4).
"Wehavealsocorrectedthetexttoshowthatweusedatotalenergyfunctionalassuggestedbythereviewer.
Inpage4,line70:"…weemployedquantummechanicalabinitiosimulationsbasedondensityfunctionaltheory(DFT)usingatotalenergyvdWfunctionaltoresolve…"Page8,line155:"…canbeexplainedattwotheoreticallevels,bothbyabinitiosimulationswithvdW-functionals,…"1.
Y.
Ma,Y.
Dai,M.
Guo,C.
NiuandB.
Huang.
GrapheneadhesiononMoS2monolayer:Anabinitiostudy.
Nanoscale3,3883(2011).
2.
W.
Hu,T.
Wang,R.
ZhangandJ.
Yang.
EffectsofinterlayercouplingandelectricfieldsontheelectronicstructuresofgrapheneandMoS2heterobilayers.
J.
Mat.
Chem.
C4,1776(2016).
3.
X.
LiuandZ.
Li.
ElectricFieldandStrainEffectonGraphene-MoS2HybridStructure:AbInitioCalculations.
J.
Phys.
Chem.
Lett.
6,3269(2015).
3)Minorcomments:Whynotusethewordasymmetricthroughout,andnotuseanisotropic.
Thereadermightbelieveitreferstoanisotropicsusceptibility,(i.
e.
dipoleforminginthexyplane),butthatisnotthetopicofthispaper.
Someabbreviationsareundefinied,inparticularintheexperimentalsection.
MaybealsoavoidusingGasabbreivationsbothinRamanspectroscopyandfordescribingthestructure.
ResponseWehavereviewedthemanuscriptthoroughlyusingtheword"asymmetric"insteadof"anisotropic"throughoutthetext.
Wehavealsodefinedunclearabbreviationsinthetext.
Page4,line87:"achievedbytworoundsofpolymethyl-methacrylate(PMMA)transfer…"4Page5,line99:"Thecorrespondingatomicforcemicroscopy(AFM)imageoftheheterostructureonAuisdisplayed…"Page6,line117:"VCPDisthecontactpotentialdifference(CPD)duetothemismatch…"Wehavemodifiedthroughoutthetexttheabbreviationof"graphene"by"G",andnowuse"graphene"insteadfordescribingthestructures.
REVIEWERS'COMMENTS:Reviewer#2(RemarkstotheAuthor):Theauthorshaveaddressedbothconcernsinasatisfactorymanner.
Irecommenditforpublication.