• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Raman scattering study ofmagnetic layered M PS3 crystals(M=M n,Fe,Ni)*

    2019-05-11 07:36:34YiMengWang王藝朦JianFengZhang張建豐ChengHeLi李承賀XiaoLiMa馬肖莉JianTingJi籍建葶FengJin金峰HeChangLei雷和暢KaiLiu劉凱
    Chinese Physics B 2019年5期
    關(guān)鍵詞:金峰劉凱

    Yi-MengWang(王藝朦),Jian-Feng Zhang(張建豐),Cheng-He Li(李承賀),Xiao-LiMa(馬肖莉),Jian-Ting Ji(籍建葶),Feng Jin(金峰),He-Chang Lei(雷和暢),Kai Liu(劉凱),

    Wei-Lu Zhang(張瑋璐)3,and Qing-M ing Zhang(張清明)2,4,?

    1DepartmentofPhysics,Renm in University ofChina,Beijing 100872,China

    2Beijing National Laboratory forCondensed MatterPhysics,Institute ofPhysics,Chinese Academy ofSciences,Beijing 100190,China

    3DepartmentofEngineering and Applied Sciences,Sophia University,7-1 Kioi-cho,Chiyoda-ku,Tokyo 102-8554,Japan

    4SchoolofPhysicalScience and Technology,Lanzhou University,Lanzhou 730000,China

    (Received 12 February 2019;revisedmanuscript received 16March 2019;published online8 April2019)

    Keywords:Raman scattering,two-dimensionalmagnetic van der Waalsmaterials,lattice dynam ics,mag netism

    1.Introduction

    One of the current research interests in two-dimensional(2D)materials focuses on magnetic van der Waals(vdW)materials,due to the intriguing physical properties for both fundamental research and potential applications in optoelectronics,spintronics,and valleytronics. A number of potentially magnetic single-layer vdW materials have recently been proposed,including V-based dichalcogenides,CrGeTe3ternary tritellurides,and CrX3trihalides.Studies on CrI3reveal that it has a stable ferromagnetic(FM)ordering in 2D form and a little change of layer-number dependence of Curie temperatures.[1–5]This hasattracted a lotof attention in other magnetic vdW crystals thatare similar to CrI3.[6–12]

    Recently,many studieshave focused on themagnetic van derWaalscrystals M P X3,which resemblesim ilar latticestructure and chem ical composition.[13–16]M P X3is a fam ily of 2D vdW layered crystals that have been prepared and studied for two decades.The structure of bulk M PS3is similar to CrI3which adopts themonoclinic A lCl3structure(pointgroup C2h).The layer structure isanchored by(P2X6)4-bipyram ids in a triangular latticewhich provide enclosures for transition metal(TM)atoms arranged in a hexagonal array.[17–23]The monolayer M PS3has a perfect honeycomb lattice similar to graphene.Formagnetism in M PS3,the intralayermagnetic structuresareantiferromagnetic(AF).However,depending on thevariety of TM atoms,magnetic structurespossessvery rich types.ForMnPS3material,the AF phase transition temperature TNis 78 K.Themagneticmoment is 3.5μB[23]and the spin lies in the ab plane with inclined angle.Themagnetic structure of MnPS3in the ab plane is N′eel AF in which the spin of the two adjacentmagnetic ions is reversed and the magnetism along the c-axis is FM ordering.For FePS3,its TNis 120 K and the spinmoment is along the c-axis.In the ab plane,themagnetic structure is zigzag-type AF ordering in which the two adjacentmagnetic ionsare the same and are opposite to the third neighbor.A long the c-axis,themagnetic order is AF type.For NiPS3,its TNis 150 K and the angle between the spin and the c-axis is less than 30°.The intralayer magnetic structure of NiPS3is zigzag-typewhich is the same as FePS3,while the interlayermagnetic order is FM type.[10]

    Raman is a useful tool to study the structure and magnetic properties of ultrathin vdW single crystals.Meanwhile,thereare severalspectroscopic studies in FePS3and NiPS3.In the previous studies of thin layer FePS3and NiPS3,two different point groups,C2hand D3d,have been proposed when discussing the phonon modes and the lattice structure.[13,14]However,no consensushasyetbeen reached.The information on MnPS3is still lacking.A comparative study of the phonon spectra in M PS3(M=Mn,Fe,Ni)is important for the clarif ication of this issue.Moreover,the temperature dependence behaviorsofmagnetism in M PS3havenotbeen studied ordiscussed in detail.Therefore,thiscalls forasystematic research of the phonon spectra andmagnetic properties in M PS3materialswith different transitionmetals.

    In this paper,we present temperature-dependent and polarization-resolved Raman spectroscopy study on layered M PS3(M=Mn,Fe,Ni)single crystals.Almost all of the Raman active phonons are observed,and the phonon mode assignments aremade by symmetry analysis and comparison with f irst principle calculations.In particular,we conduct a comparative study of Raman spectra in MnPS3,FePS3,and NiPS3,which share identical lattice structure butexhibit distinctmagnetic order,and their temperature evolution crosses themagnetic transition.Consequently,we provide comprehensive information on the relation of the latticedynamicsand magnetism in the M PS3system.

    2.Experimentaland calculationmethods

    Single crystals of M PS3(M=Mn,Fe,Ni)were grown by chem ical vapor transport(CVT)method.The crystal naturally cleaves along the(001)surface,form ing MnPS3f lakes weakly bonded by van derWaals force.In thisexperiment,the MnPS3f lakes were cleaved from bulk single crystals,transferred on to silicon substrates,and capped with 90 nm silicon oxide(SiO2)because of the transparent characteristic.The SiO2capping layer does not induce any extra signal in theenergy rangewe are interested in and can enhance Raman scattering signal intensity from the sample.The FePS3and NiPS3singlecrystalswere tested on thecopperholderdirectly.The temperature-dependentand polarization-resolved Raman spectra were collected in a backscattering conf iguration using an HR800 spectrometer(Jobin Yvon)equipped with a liquid-nitrogen-cooled charge-coupled device(CCD)and volume Bragg gratings.The sampleswereplaced in an ultrahigh vacuum(UHV)cryostatwith a vacuum of~10-8mbar.A λ=633 nm laser was focused to a 5×5μm2spot on the ab surface of the sample.The scattered signalwas collected through a50×long focus-length objective,and dispersedwith a 600 grooves/mm grating.The laser powerwas keptatapproximately~1.4 mW.We def ine X and Y axes inside the crystallographic ab plane.X is perpendicular to the b axisand Y isalong the b axis.Z isperpendicular to X and Y.

    First-principles calculationswere employed to work out the Brillouin zone-center(Gamma point)phonon modes of MnPS3.The projector augmented wave(PAW)method implemented in the Vienna ab initio simulation package(VASP)package was used to describe core electrons.[24–28]For the exchange–correlation potential,the generalized gradient approximation(GGA)of Perdew–Burke–Ernzerhof formulawas adopted.[29]To describe the van derWaals interaction in layered systems not included in the conventional density functional theory,the vdW-optB86b functional was chosen.[30]The on-site Coulomb repulsion among the localized Mn 3d electronswasalso included by using the formalism(GGA+U)of Dudarev et al.[31]with an effective U=5 eV.The kinetic energy cutoffof theplane-wavebasiswassettobe300eV.The simulations were carried outwith a triclinic cell containing twoMn atoms,two Patoms,and six Satoms,inwhich twoMn atoms took the antiferromagnetic order.An 8×8×8 k-point mesh for the Brillouin zone sampling and theGaussian smearing with a w idth of 0.05 eV around the Ferm i surface were employed.In structureoptim ization,both cellparametersand internalatom ic positionswere allowed to relax untilall forces were smaller than 0.01 eV/?A.When the equilibrium structure wasobtained,thephononmodesatBrillouin zone centerwere calculated by using the dynamicmatrixmethod.The calculationswith a 10-atom cellgave 27 opticalmodes.However,to illustrate thedisplacementpatternsof phononmodes,weshow our results in a20-atom supercelldeduced from the real-space translational invarianceof the10-atom cell;as in Ref.[32].

    3.Resultsand discussion

    The M PS3crystal has a monoclinic structure with C2hpointgroup(spacegroup C2/m).With 10 atoms in aprim itive unitcell,wehavea totalof 30 phononmodes.At theΓpoint,there are 8Ag+7BgRaman activemodes.The corresponding Raman tensorsare

    This leads to different angular dependence of the phonon intensity I(θ)for the Agand Bgmodes in Raman spectrawhen the incident/scattered light polarizations(ei/es)rotate inside the ab plane

    whereθis def ined as the angle between eiand the Y axis.From Eqs.(1)and(2),we f ind thatwhenθ=0,theAgphonon only appears under parallel polarization and the Bgphonon only appears under cross polarization;whenθ=π/4,the Agphonon appears under both parallel and cross polarizations,while the Bgphonon only appearsunderparallelpolarization.

    Fig.1.(a)Unpolarized Raman spectrum ofMnPS3 collected at room temperature.(b)Polarized Raman spectra ofMnPS3 at room temperature under Z(XX)ˉZ(red line)and Z(XY)ˉZ(blue line)scattering geometry.Inset:the XYZ/abc coordinates.(c)Intensitymap of Raman spectra of MnPS3 under parallelpolarization scattering geometry asa function of Raman shiftand angle.(d)Sameas(c),butunder crosspolarization geometry.

    Table1.Calculated and experimentalopticalphononmodes(in cm-1)forMnPS3.Theatom icmotionsof themodesarealsogiven(see Fig.4).R and IR denote Raman and infrared activities,respectively.

    In Figs.1(a)and 1(b),we show Raman spectraofMnPS3at room temperature.The peak at520.7 cm-1is from the Si substrate.A ll the remaining peaksare the phononsofMnPS3.

    We assign the three MnPS3phonons that only appear in XX polarization to Agmode.However,no phonon modes only appear in the XY scattering geometry.In Figs.1(c)and 1(d),we track the angular dependence of the phonon intensity under parallel and cross polarizations.Surprisingly,we do not observe anymode that reduces to zero intensity atθ=π/4.

    To f ind the origin of the remaining four phonon modes,we consider a change of the lattice symmetry in the 2D van derWaalsmaterials.Formonolayer MnPS3,the lattice point group is D3d.At theΓpoint,there are 3A1g+5EgRaman activemodes.The corresponding Raman tensorsare In this case,the 3A1gphonons show maximum intensity under XX polarization conf iguration and zero intensity under XY polarization conf iguration,while the intensity of the 5Egphononsdoesnotshow strong angulardependence.

    The bulk crystals consistof ABC-stacked single layer assemblies thatareheld togetherby van derWaals forces.Thus,forbulk crystals,theC3symmetry along the c axishasbroken compared to themonolayer crystals.Becauseof the symmetry breaking,the Egmode in D3dsymmetry w ill degenerate into Agand Bgmodeswhich have similarenergies in C2hsymmetry.Based on the discussion above,forMnPS3,the observed phononsare:115.5 cm-1(1Ag,1Bg),153.8 cm-1(2Ag,2Bg),245.0 cm-1(3Ag),270.0 cm-1(4Ag,3Bg),383.2 cm-1(5Ag),567.5 cm-1(6Ag,4Bg),and 580.3 cm-1(7Ag).

    To relate theobservedmodesatcertain frequencies to the specif ic atomic displacements,we conduct the f irst-principles calculations.The experimentaland calculatedmode frequencies are summarized in Table 1.The calculated phonon frequenciesare in good agreementwith theexperimentaldata.In Fig.2,we show theatomic displacementsof allof the Raman activemodes.

    Using the same analysismethod for MnPS3,we determ ine the phononmodes for FePS3and NiPS3.As shown in Fig.3(a),for FePS3,the observed phonons are:94.9 cm-1(1Ag,1Bg),156.9 cm-1(2Ag,2Bg),223.3 cm-1(3Ag,3Bg),245.8 cm-1(4Ag),275.2 cm-1(5Ag,4Bg),380.9 cm-1(6Ag),and 582.9 cm-1(7Ag).Near275.2 cm-1,thepeak energiesare slightly differentunder Z(XX)ˉZ and Z(XY)ˉZ scatteringgeometry,which suggests that thereare two differentmodesatvery close energy.The splitting of the peak is found at low temperatures,indicating that thesymmetry ofbulk crystals isC2h.The obvious difference between the two channels of FePS3at room temperature may be due to the different evolution of different phonon peakswith temperature.The NiPS3Raman spectra are shown in Fig.4,where the observed phonon modes are:132.2 cm-1(1Ag,1Bg),177.4 cm-1(2Ag,2Bg),234.8 cm-1(3Ag,3Bg),255.1 cm-1(4Ag),280.7 cm-1(5Ag,4Bg),384.8 cm-1(6Ag),and 589.2 cm-1(7Ag).The experimental resultsof FePS3and NiPS3are ingood agreementwith the theoretical calculations.[6]

    In Fig.5,we show the Raman spectra in M PS3(M=Mn,Fe,Ni)at 10 K,TN,and 300 K.For all of the samples,we observe that the phononmode(~260 cm-1at300 K)splits into two peaks at the lowest temperature.We attribute this to the narrow ing of the phonon linew idth at low temperature.Moreover,we observe two unusual temperature-dependent behaviors for M PS3(M=Mn,Fe,Ni).Firstly,for FePS3,three new phononmodes appear in themagnetic order phase(T<TN),while we do not observe such additionalmodes in MnPS3or NiPS3.This different behavior in FePS3must be related to its specialmagnetic structure.We attribute this to the AF interlayermagnetic structure in FePS3,which doubles the lattice unit cell if there is a strong spin–lattice coupling,

    Fig.2.Vibration patternsofallRamanmodesobserved in MnPS3.Themodesymmetry,opticalactivity,and experimental(calculated)phonon frequency(theunitis cm-1)arealso listed below each pattern.

    Fig.3.(a)Raman spectrum of FePS3 collected at room temperature.(b)Polarized Raman spectrum of FePS3 at room temperature under different polarization conf igurations.(c)The angle-dependent Raman spectrum of FePS3 in parallel polarization channel.(d)The angledependentRaman spectrum of FePS3 in cross polarization channel.

    Fig.4.(a)Unpolarized Raman spectrum of NiPS3 at room temperature.(b)Polarized Raman spectrum of NiPS3 at room temperature under different polarization conf igurations.(c)The angle-dependent Raman spectrum of NiPS3 in parallel polarization channel.(d)The angle-dependentRaman spectrum of NiPS3 in crosspolarization channel.

    and,consequently,the zoneboundarymodesare folded to the Γpoint.In Mn/NiPS3,the interlayermagnetic structure is FM,and w illnotdouble the lattice unitcell.Thisexplains the non-observation of additionalmodes in Mn/NiPS3.Secondly,forMnPS3and NiPS3,they have the same out-of-planemagnetism but different in-planemagnetism.The in-planemagnetism is zig-zag type AF in NiPS3,while the in-planemagnetism is N′eel type AF in MnPS3.We f ind that the energy of the 150 cm-1phononmode at10 K ismuch lower than that at 300 K in MnPS3,which is unusual for a normal phonon mode.The lower energy of thismode at 10 K indicates its coupling with spins,whichmodulates the self-energy of this phonon and causes the lower energy of it.This indicates that the in-planeN′eelAF inMnPS3favorsaspin–phonon coupling compared to the in-plane zig-zag AF in NiPS3and FePS3.Comparing the ab in-plane and the c axis out-of-planemagnetic structureof the series,it is found thatspin–phonon coupling isgeneral in this fam ilymaterialsand differentmagnetic structuresw ill have different inf luences on the phonons and magnons.

    Fig.5.The temperature dependence of Raman spectra of MnPS3,FePS3,and NiPS3.The dashed line indicates the softened mode in MnPS3 and thearrows indicate thenew modes in FePS3 below T N.

    4.Conclusion and perspectives

    We report the experimental and f irst-principles calculation for the temperature dependentand polarization resolved Raman spectroscopy on the lattice dynamics of M PS3(M=Mn,Fe,Ni)single crystals.We identify 7 outof11Raman active phonons and the corresponding atom ic displacements.In addition,we observe additional phonons appearing in FePS3in themagnetic ordered state,while there is no new phonon mode in MnPS3and NiPS3.Thismagneto-elastic effect is related to uniqueAForderalong the c axisin FePS3,which doubles the unit celland folds the zone boundarymode to theΓ point.ForMnPS3,partof the phononsare softened below TN,suggesting spin–phonon coupling in thismaterial.Thepresent study provides the system information on the latticedynamics andmagneticof M PS3(M=Mn,Fe,Ni)and isof signif icance for theexploration of structuralandmagnetic propertiesof the monolayer M P X3.

    Acknow ledgments

    Computational resourceshavebeen provided by thePhysical Laboratory of High Performance Computing at Renmin University of China.The atom ic structures and vibrational displacement patterns were prepared with the XCRYSDEN program.[33]

    猜你喜歡
    金峰劉凱
    QUASIPERIODICITY OF TRANSCENDENTAL MEROMORPHIC FUNCTIONS*
    蘇州金峰物流設(shè)備有限公司
    航空航天模型實(shí)踐活動(dòng)手冊
    蘇州金峰物流設(shè)備有限公司
    Speedup of self-propelled helical swimmers in a long cylindrical pipe
    Crystal growth and magnetic properties of quantum spin liquid candidate KErTe2?
    High-resolution angle-resolved photoemission study of large magnetoresistance topological semimetal CaAl4?
    蘇州金峰物流設(shè)備有限公司
    左手“反腐”,右手貪腐
    清風(fēng)(2017年11期)2017-11-24 08:03:21
    Numerical simulation of submarine landslide tsunamis using particle based methods*
    ponron亚洲| 午夜影院日韩av| 高清日韩中文字幕在线| 露出奶头的视频| 一区二区三区免费毛片| 极品教师在线视频| 国产伦在线观看视频一区| 一个人看的www免费观看视频| 91在线精品国自产拍蜜月| 国产亚洲av嫩草精品影院| 日本撒尿小便嘘嘘汇集6| 国产又黄又爽又无遮挡在线| 国产精品国产高清国产av| 欧美又色又爽又黄视频| 久久久久久久久久黄片| av视频在线观看入口| 美女高潮的动态| 啦啦啦观看免费观看视频高清| 欧美日韩综合久久久久久 | 波多野结衣高清作品| 97热精品久久久久久| 精品久久久久久成人av| 成人国产综合亚洲| 日韩中字成人| 亚洲七黄色美女视频| 久久99热6这里只有精品| 天堂av国产一区二区熟女人妻| 九九在线视频观看精品| 日本色播在线视频| 亚洲av一区综合| bbb黄色大片| 国内精品久久久久精免费| av.在线天堂| 色综合亚洲欧美另类图片| 女人十人毛片免费观看3o分钟| 成人鲁丝片一二三区免费| 亚洲中文日韩欧美视频| 又粗又爽又猛毛片免费看| 欧美精品国产亚洲| 亚洲欧美日韩高清专用| 人妻丰满熟妇av一区二区三区| 九九在线视频观看精品| 99久久中文字幕三级久久日本| 精品久久久久久久末码| 亚洲第一电影网av| 国产老妇女一区| 日韩欧美一区二区三区在线观看| 久久午夜福利片| 99热这里只有精品一区| 亚洲av五月六月丁香网| 午夜福利欧美成人| 少妇猛男粗大的猛烈进出视频 | 97热精品久久久久久| 狂野欧美白嫩少妇大欣赏| 国产成人aa在线观看| 亚洲国产日韩欧美精品在线观看| 熟女电影av网| 精华霜和精华液先用哪个| 99在线人妻在线中文字幕| 91久久精品国产一区二区成人| 午夜精品在线福利| 美女高潮的动态| 国产又黄又爽又无遮挡在线| 99久久成人亚洲精品观看| 久久久精品大字幕| 联通29元200g的流量卡| 内射极品少妇av片p| 日本黄色视频三级网站网址| 91午夜精品亚洲一区二区三区 | 亚洲最大成人手机在线| 麻豆精品久久久久久蜜桃| 亚洲国产精品久久男人天堂| 波多野结衣巨乳人妻| 国产精品1区2区在线观看.| 永久网站在线| 老女人水多毛片| 在线播放无遮挡| 日本-黄色视频高清免费观看| 国内精品久久久久久久电影| 99热6这里只有精品| 国产在视频线在精品| 黄色配什么色好看| 久久欧美精品欧美久久欧美| 久久精品人妻少妇| 一进一出好大好爽视频| 精品免费久久久久久久清纯| 啦啦啦啦在线视频资源| 午夜日韩欧美国产| 亚洲欧美日韩东京热| 全区人妻精品视频| av国产免费在线观看| 免费不卡的大黄色大毛片视频在线观看 | 亚洲国产精品sss在线观看| 他把我摸到了高潮在线观看| 淫秽高清视频在线观看| 欧美在线一区亚洲| 一进一出抽搐动态| 国产精品久久久久久久久免| 国内精品久久久久精免费| h日本视频在线播放| 午夜免费成人在线视频| 一进一出好大好爽视频| 午夜福利视频1000在线观看| 国产av麻豆久久久久久久| 成人国产一区最新在线观看| 一级毛片久久久久久久久女| 国产精品永久免费网站| 在线天堂最新版资源| 久久久久久久久久黄片| 国产真实乱freesex| 真人做人爱边吃奶动态| 精品久久久久久,| 久久久久久久精品吃奶| 国产高清三级在线| 亚洲 国产 在线| 舔av片在线| 男人狂女人下面高潮的视频| 亚洲av二区三区四区| 免费av毛片视频| 亚洲无线在线观看| 国产中年淑女户外野战色| 亚洲在线观看片| 亚洲av五月六月丁香网| 村上凉子中文字幕在线| 欧美性猛交黑人性爽| 久久天躁狠狠躁夜夜2o2o| 人妻少妇偷人精品九色| 别揉我奶头 嗯啊视频| 天堂av国产一区二区熟女人妻| 三级男女做爰猛烈吃奶摸视频| 婷婷精品国产亚洲av在线| 99热网站在线观看| 偷拍熟女少妇极品色| 亚洲四区av| 色av中文字幕| 少妇的逼水好多| 日本黄大片高清| 免费电影在线观看免费观看| 真人一进一出gif抽搐免费| 99久久精品一区二区三区| 最好的美女福利视频网| 国模一区二区三区四区视频| 可以在线观看毛片的网站| 大型黄色视频在线免费观看| 亚洲av第一区精品v没综合| 久久精品国产亚洲av天美| av.在线天堂| 亚洲精品国产成人久久av| 免费看av在线观看网站| 精品不卡国产一区二区三区| 琪琪午夜伦伦电影理论片6080| 女人被狂操c到高潮| 一个人看的www免费观看视频| 精品午夜福利在线看| 精品无人区乱码1区二区| 国内精品一区二区在线观看| 婷婷精品国产亚洲av在线| 亚洲aⅴ乱码一区二区在线播放| 国产大屁股一区二区在线视频| 人妻夜夜爽99麻豆av| 亚洲性夜色夜夜综合| 成人二区视频| 永久网站在线| 日韩强制内射视频| 日韩欧美在线二视频| 欧美日韩综合久久久久久 | 亚洲精品456在线播放app | 乱系列少妇在线播放| 亚洲,欧美,日韩| 日韩欧美一区二区三区在线观看| 非洲黑人性xxxx精品又粗又长| 伊人久久精品亚洲午夜| 日本精品一区二区三区蜜桃| 啦啦啦啦在线视频资源| 999久久久精品免费观看国产| 国产一区二区三区在线臀色熟女| 校园春色视频在线观看| 国内少妇人妻偷人精品xxx网站| 偷拍熟女少妇极品色| av黄色大香蕉| 日本五十路高清| 日韩av在线大香蕉| 99精品在免费线老司机午夜| 亚洲精品日韩av片在线观看| 亚洲av免费高清在线观看| 日日摸夜夜添夜夜添av毛片 | 亚洲欧美日韩高清在线视频| 一级a爱片免费观看的视频| 日韩高清综合在线| 欧美日本视频| 免费不卡的大黄色大毛片视频在线观看 | 久99久视频精品免费| 两性午夜刺激爽爽歪歪视频在线观看| 亚洲av免费在线观看| 一级黄片播放器| .国产精品久久| 女生性感内裤真人,穿戴方法视频| 亚洲欧美精品综合久久99| 欧美三级亚洲精品| 搡老妇女老女人老熟妇| 免费观看精品视频网站| 国内揄拍国产精品人妻在线| 在线免费观看不下载黄p国产 | 国产精华一区二区三区| 日日摸夜夜添夜夜添av毛片 | 看片在线看免费视频| 欧美日韩精品成人综合77777| 在现免费观看毛片| 亚洲色图av天堂| 色哟哟·www| 欧美成人免费av一区二区三区| 国内精品美女久久久久久| 欧美性感艳星| 亚洲在线自拍视频| www日本黄色视频网| 1024手机看黄色片| 老司机深夜福利视频在线观看| 国产精品,欧美在线| 国产视频内射| 国产一级毛片七仙女欲春2| 日韩欧美免费精品| 黄色欧美视频在线观看| 国产高清激情床上av| 国产精品美女特级片免费视频播放器| 亚洲人成网站在线播| 亚洲午夜理论影院| 国产男人的电影天堂91| 午夜福利成人在线免费观看| 神马国产精品三级电影在线观看| 欧美成人一区二区免费高清观看| 久久久久久久久久成人| 国产一区二区亚洲精品在线观看| 国产在视频线在精品| 亚洲乱码一区二区免费版| 国产亚洲精品久久久com| 欧美日韩国产亚洲二区| 十八禁网站免费在线| 欧美成人免费av一区二区三区| 一区二区三区高清视频在线| 日韩高清综合在线| 黄色配什么色好看| 听说在线观看完整版免费高清| 天堂影院成人在线观看| 亚洲成人中文字幕在线播放| 熟女人妻精品中文字幕| 久久精品91蜜桃| 嫩草影院新地址| 精品久久久噜噜| 国产 一区精品| 好男人在线观看高清免费视频| 国产精品一区二区三区四区免费观看 | 九九热线精品视视频播放| 日韩欧美在线二视频| 日本五十路高清| 成年人黄色毛片网站| 国产精品一区二区三区四区免费观看 | 99九九线精品视频在线观看视频| 联通29元200g的流量卡| 久久中文看片网| 精品日产1卡2卡| 国产又黄又爽又无遮挡在线| 午夜福利欧美成人| 美女高潮的动态| 我的老师免费观看完整版| 欧美激情在线99| 看黄色毛片网站| 高清日韩中文字幕在线| 亚洲avbb在线观看| 亚洲乱码一区二区免费版| 麻豆国产av国片精品| 老熟妇乱子伦视频在线观看| 俄罗斯特黄特色一大片| 亚洲av中文字字幕乱码综合| 亚洲av免费在线观看| 欧美另类亚洲清纯唯美| 2021天堂中文幕一二区在线观| 亚洲av免费高清在线观看| 成年版毛片免费区| 制服丝袜大香蕉在线| 午夜精品一区二区三区免费看| 午夜a级毛片| 无人区码免费观看不卡| 伦理电影大哥的女人| 男女下面进入的视频免费午夜| videossex国产| 成人欧美大片| 日日撸夜夜添| 成人二区视频| 日本与韩国留学比较| 日韩亚洲欧美综合| 国产熟女欧美一区二区| 99国产精品一区二区蜜桃av| 欧美高清成人免费视频www| 香蕉av资源在线| 老司机午夜福利在线观看视频| 午夜福利高清视频| 国内精品宾馆在线| 欧美日韩综合久久久久久 | 啦啦啦韩国在线观看视频| 国产精品久久久久久精品电影| 干丝袜人妻中文字幕| 嫩草影视91久久| 久久九九热精品免费| 国产精品1区2区在线观看.| 观看美女的网站| 久久久久久久久中文| 久久精品影院6| 国产又黄又爽又无遮挡在线| 香蕉av资源在线| 精品99又大又爽又粗少妇毛片 | 内地一区二区视频在线| 精品人妻视频免费看| 狂野欧美白嫩少妇大欣赏| 精品一区二区三区人妻视频| 日本一二三区视频观看| 欧美区成人在线视频| 少妇猛男粗大的猛烈进出视频 | 精品久久久噜噜| 他把我摸到了高潮在线观看| 亚洲第一电影网av| 精品一区二区免费观看| 黄色丝袜av网址大全| av国产免费在线观看| 两人在一起打扑克的视频| ponron亚洲| 久久久色成人| 我的老师免费观看完整版| 桃红色精品国产亚洲av| 日韩中文字幕欧美一区二区| 99riav亚洲国产免费| 黄色日韩在线| 男女视频在线观看网站免费| 婷婷亚洲欧美| 天天躁日日操中文字幕| 欧美激情久久久久久爽电影| 国产高清有码在线观看视频| 国产精品乱码一区二三区的特点| а√天堂www在线а√下载| 国产伦在线观看视频一区| 嫩草影院精品99| 天堂av国产一区二区熟女人妻| 十八禁网站免费在线| 亚洲av成人精品一区久久| 香蕉av资源在线| 国产精品永久免费网站| 国产精品久久久久久精品电影| 欧洲精品卡2卡3卡4卡5卡区| 久久99热这里只有精品18| 蜜桃久久精品国产亚洲av| 国产一区二区在线观看日韩| 成熟少妇高潮喷水视频| 国内揄拍国产精品人妻在线| 色尼玛亚洲综合影院| 欧美bdsm另类| 九九爱精品视频在线观看| 久久精品国产自在天天线| 国产单亲对白刺激| 亚洲国产精品sss在线观看| 啦啦啦啦在线视频资源| 亚洲真实伦在线观看| bbb黄色大片| 大型黄色视频在线免费观看| 精品无人区乱码1区二区| 男女啪啪激烈高潮av片| 日韩 亚洲 欧美在线| 一区二区三区激情视频| 亚洲av一区综合| 国产在线精品亚洲第一网站| 日本-黄色视频高清免费观看| 九九热线精品视视频播放| 久久久色成人| 中文在线观看免费www的网站| 国产免费一级a男人的天堂| 乱人视频在线观看| 日本在线视频免费播放| av.在线天堂| 超碰av人人做人人爽久久| 十八禁国产超污无遮挡网站| 日本五十路高清| 亚洲欧美清纯卡通| 亚洲精华国产精华液的使用体验 | 欧美最黄视频在线播放免费| 欧美+亚洲+日韩+国产| 欧美zozozo另类| 国产av麻豆久久久久久久| 精品一区二区免费观看| 在线看三级毛片| 亚洲第一区二区三区不卡| 午夜亚洲福利在线播放| 免费人成在线观看视频色| 草草在线视频免费看| 99热这里只有是精品在线观看| 永久网站在线| 99久久无色码亚洲精品果冻| 午夜视频国产福利| 精品乱码久久久久久99久播| 欧美日韩亚洲国产一区二区在线观看| 亚洲精品成人久久久久久| 欧美成人免费av一区二区三区| 久久精品国产自在天天线| 欧美高清性xxxxhd video| 国内揄拍国产精品人妻在线| 久久人妻av系列| 欧美黑人欧美精品刺激| 99久久精品一区二区三区| 九九热线精品视视频播放| 国产精品不卡视频一区二区| 一区二区三区四区激情视频 | 亚洲中文日韩欧美视频| 日本免费a在线| 久久精品国产亚洲av涩爱 | 最近视频中文字幕2019在线8| 日韩在线高清观看一区二区三区 | 国产欧美日韩精品一区二区| 黄色视频,在线免费观看| 欧美绝顶高潮抽搐喷水| 亚洲精华国产精华精| 亚洲成人免费电影在线观看| 亚洲国产色片| 国产男靠女视频免费网站| 干丝袜人妻中文字幕| 欧美bdsm另类| av在线老鸭窝| 成年女人永久免费观看视频| 伦精品一区二区三区| 69av精品久久久久久| 一级黄色大片毛片| 一夜夜www| 99久久成人亚洲精品观看| 九九久久精品国产亚洲av麻豆| 日韩 亚洲 欧美在线| 身体一侧抽搐| a在线观看视频网站| 欧美激情国产日韩精品一区| 91久久精品国产一区二区三区| 日本一本二区三区精品| 成人国产麻豆网| 人妻久久中文字幕网| 婷婷色综合大香蕉| 老司机福利观看| 成人三级黄色视频| 日本黄色片子视频| 亚洲国产精品成人综合色| 精品久久久久久久久久免费视频| 一a级毛片在线观看| 日本黄色片子视频| 国产乱人视频| 毛片女人毛片| 精品不卡国产一区二区三区| 欧美在线一区亚洲| 国产成人一区二区在线| 国产一区二区激情短视频| 黄色欧美视频在线观看| 国产私拍福利视频在线观看| 色尼玛亚洲综合影院| 久久精品国产自在天天线| 女人被狂操c到高潮| 99国产极品粉嫩在线观看| 国产精品一区www在线观看 | 乱系列少妇在线播放| 国产精品福利在线免费观看| 九九爱精品视频在线观看| 深夜精品福利| 日韩在线高清观看一区二区三区 | 亚洲午夜理论影院| 亚洲黑人精品在线| 我的老师免费观看完整版| 韩国av在线不卡| 国产真实伦视频高清在线观看 | 国产av不卡久久| 韩国av一区二区三区四区| 69人妻影院| 小说图片视频综合网站| 一进一出抽搐动态| 3wmmmm亚洲av在线观看| 久久久久久久亚洲中文字幕| 淫秽高清视频在线观看| 国产白丝娇喘喷水9色精品| 禁无遮挡网站| 人人妻,人人澡人人爽秒播| 一卡2卡三卡四卡精品乱码亚洲| 他把我摸到了高潮在线观看| 真人做人爱边吃奶动态| 69av精品久久久久久| 成年女人看的毛片在线观看| 亚洲成a人片在线一区二区| 午夜福利欧美成人| 国内精品久久久久精免费| 国产精品精品国产色婷婷| 成年版毛片免费区| 成人av在线播放网站| 精品人妻视频免费看| 一本精品99久久精品77| a级毛片免费高清观看在线播放| 日本熟妇午夜| 天天躁日日操中文字幕| 国产精品98久久久久久宅男小说| 欧美xxxx黑人xx丫x性爽| 老熟妇仑乱视频hdxx| 很黄的视频免费| 久久久午夜欧美精品| 午夜激情欧美在线| 成人国产麻豆网| 欧美最黄视频在线播放免费| 国产高清有码在线观看视频| 精品一区二区三区人妻视频| 国产单亲对白刺激| 深夜精品福利| 国产免费男女视频| 久久国内精品自在自线图片| 人人妻,人人澡人人爽秒播| 国产久久久一区二区三区| 哪里可以看免费的av片| 内射极品少妇av片p| 日本一二三区视频观看| 欧美日本亚洲视频在线播放| 国产综合懂色| 深爱激情五月婷婷| 夜夜看夜夜爽夜夜摸| 国产视频内射| 我的女老师完整版在线观看| 在线播放无遮挡| 成人无遮挡网站| 波多野结衣高清无吗| 国产久久久一区二区三区| 国产一区二区亚洲精品在线观看| 国产白丝娇喘喷水9色精品| 国产人妻一区二区三区在| 少妇人妻一区二区三区视频| 九色国产91popny在线| 美女xxoo啪啪120秒动态图| 亚洲人成网站在线播放欧美日韩| 两人在一起打扑克的视频| 国产精品一及| 国产伦在线观看视频一区| 男插女下体视频免费在线播放| 亚洲精品一区av在线观看| 中文在线观看免费www的网站| 亚洲性夜色夜夜综合| 亚洲人成网站在线播放欧美日韩| 国产亚洲欧美98| 99热只有精品国产| 久久精品国产亚洲av涩爱 | 色播亚洲综合网| 两个人的视频大全免费| 欧美成人免费av一区二区三区| 天堂√8在线中文| 成人高潮视频无遮挡免费网站| 久久午夜亚洲精品久久| 3wmmmm亚洲av在线观看| 国产精品野战在线观看| 亚洲精品影视一区二区三区av| 22中文网久久字幕| 免费黄网站久久成人精品| 丰满乱子伦码专区| 欧美最新免费一区二区三区| 在线看三级毛片| 丰满人妻一区二区三区视频av| 国产精品亚洲美女久久久| 国产亚洲av嫩草精品影院| 国产 一区精品| 亚洲三级黄色毛片| 亚洲黑人精品在线| 国产精品久久久久久亚洲av鲁大| 国产精品永久免费网站| av在线天堂中文字幕| 亚洲第一区二区三区不卡| 99久国产av精品| 国产黄a三级三级三级人| 国产白丝娇喘喷水9色精品| 午夜激情福利司机影院| www.色视频.com| netflix在线观看网站| 午夜免费激情av| 成人三级黄色视频| 久久久久久久亚洲中文字幕| 成年女人永久免费观看视频| 日日摸夜夜添夜夜添av毛片 | 亚洲经典国产精华液单| 成人无遮挡网站| 91午夜精品亚洲一区二区三区 | 久久这里只有精品中国| 日韩大尺度精品在线看网址| 亚洲最大成人av| 国产白丝娇喘喷水9色精品| 99在线视频只有这里精品首页| 99国产极品粉嫩在线观看| 亚洲久久久久久中文字幕| 亚州av有码| 波多野结衣巨乳人妻| 久久6这里有精品| 亚洲中文字幕一区二区三区有码在线看| 无人区码免费观看不卡| 午夜福利欧美成人| 亚洲在线观看片| 欧美性感艳星| 波野结衣二区三区在线| 最近在线观看免费完整版| 亚洲欧美日韩无卡精品| 午夜久久久久精精品| 亚洲精品国产成人久久av| 欧美不卡视频在线免费观看| 午夜精品久久久久久毛片777| 国产精品久久久久久亚洲av鲁大| 欧美极品一区二区三区四区| 国产高清视频在线观看网站| 国产午夜精品论理片| 午夜福利在线观看吧| 午夜福利高清视频| 亚洲精品456在线播放app | 乱码一卡2卡4卡精品| 噜噜噜噜噜久久久久久91| 白带黄色成豆腐渣| 最近最新免费中文字幕在线| 亚洲成人免费电影在线观看|