Structure of Reconstructed Cu(100) Surface Induced by Dissociative Adsorption of Gaseous Oxygen

用低能电子衍射(LEED)和扫描隧道显微镜技术研究了氧气在Cu(100)表面化学吸附所形成的表面重构结构．在低覆盖度下,实验上观察到了两个有序重构的混合相,分别为c(2×2)O重构和(√2×2√2)R45°-O重构．在氧原子的覆盖度逐渐增加的过程中,c(2×2)O重构区域的面积逐渐减小．在初始氧化阶段,实验上观察到了呈条状的“锯齿”形的重构结构,这些锯齿形的结构是由相邻的局域化的c(2×2)区域的边界区域(Cu)构成的．STM实验发现,相对于其他重构区域,这些锯齿形的重构区域与有机分子之间存在更加强烈的相互作用．通过分析在不同退火温度下样品LEED衍射点的变化,研究了重构结构的热稳定性,发现三种结构的热稳定性顺序是：锯齿结构>c(2×2)O重构>(√2×2√2)R45°-O重构．     

Scanning tunneling microscopy study of surface reconstruction induced by N adsorption on Cu (100) surface

The reconstructed structure of Cu (100) surface induced by atomic N adsorption is studied by using scanning tunneling microscopy (STM). The 2D structure of copper boundary between neighbouring N covered islands is found to be sensitive to the growth conditions, e.g. N⁺ bombardment time and annealing temperature. The copper boundary experiences a transition from nano-scale stripe to nano-particle when the substrate is continuously annealed at 623~K for a longer time. A well-defined copper-stripe network can be achieved by precisely controlling the growth conditions, which highlights the possibility of producing new templates for nanofabrication.     

tetracene 分子在Ru(1010)表面的吸附结构及其电子态研究

利用紫外光电子能谱(UPS)、角分辨紫外光电子能谱(ARUPS)和扫描隧道显微镜(STM)等方法研究了tetracene分子在Ru(1010)表面上吸附的电子态，吸附位置和吸附取向.UPS实验显示，与tetracene分子有关的光电子谱峰在费米能级以下2.1, 3.5, 4.8, 6.0, 7.1和9.2 eV处；ARUPS 结果表明，tetracene分子的分子平面基本平行于衬底表面；从STM图像中可以看到tetracene分子的长轴沿［0001］和［1210］两个晶向.基于密度泛函理论的从头算计算证实了上述结论.当分子长轴沿［0001］晶向时，分子中心位置在衬底表面的“短桥位”上，当分子长轴沿［1210］晶向时，分子中心位置在衬底表面的“四原子中心空位”上. 关键词： tetracene分子 Ru(1010)表面 吸附结构 吸附电子态     

tetracene分子在Ru(100)表面的吸附结构及其电子态研究

利用紫外光电子能谱(UPS)、角分辨紫外光电子能谱(ARUPS)和扫描隧道显微镜(STM)等方法研究了tetracene分子在Ru(100)表面上吸附的电子态,吸附位置和吸附取向.UPS实验显示,与tetracene分子有关的光电子谱峰在费米能级以下2.1,3.5,4.8,6.0,7.1和9.2eV处;ARUPS结果表明,tetracene分子的分子平面基本平行于衬底表面;从STM图像中可以看到tetracene分子的长轴沿[0001]和[1■10]两个晶向.基于密度泛函理论的从头算计算证实了上述结论.当分子长轴沿[0001]晶向时,分子中心位置在衬底表面的“短桥位”上,当分子长轴沿[1210]晶向时,分子中心位置在衬底表面的“四原子中心空位”上.     

Differences in the adsorption of FePc on coinage metal surfaces

A study of the electronic and structural properties of iron phthalocyanine(FePc) molecules adsorbed on coinage metal surfaces Cu(100) and Cu(110) has been conducted by means of density functional theory calculations.The strength of the molecule-substrate interactions is interpreted in terms of the lateral adsorption geometry and the site specific electronic structure of the molecule.In the case of FePc on a(100)-oriented copper surface,the benzopyrrole leg is found to be oriented at an angle of 9° or 3° from the [01-1] substrate direction.Further,an upward bend in the molecular plane ranging from 7° to 10° is also observed;giving an almost buckled shape to the molecule.However,in the case of FePc on Cu(110),neither a bend nor a sizable rotation is observed.From the knowledge of the principle structural and electronic properties,it is concluded that FePc-Cu(100) interaction is relatively stronger than FePc-Cu(110) interaction,which is further evidenced by the charge transfer,work function changes,changes in the shape of the adsorbed molecular orbitals,and the orbital shifts.Furthermore,density of states analysis shows that the valence band level shift is surface-and site-dependent.     

Density functional theory calculations of tetracene on low index surfaces of copper crystal

This paper carries out the density functional theory calculations to study the adsorbate--substrate interaction between tetracene and Cu substrates (Cu (110) and Cu (100) surface). On each of the surfaces, two kinds of geometry are calculated, namely `flat-lying' mode and `upright standing' mode. For `flat-lying' geometry, the molecule is found to be aligned with its longer molecular axis along close-packed direction of the substrate surfaces. For `upright standing' geometry, the long axis of tetracene is found to be parallel to the surface normal of the substrate on Cu (110) surface. However, tetracene appears as `tilted' mode on Cu (100) surface. Structures with `flat-lying' mode have much larger adsorption energy and charge transfer upon adsorption than that with `upright standing' mode, indicating the preference of `flat-lying' geometry on both Cu (110) and Cu (100) surface.     

Ag(110)表面吸附酞菁铜分子的紫外光电子谱研究

用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附,随着酞菁铜分子覆盖度增加,衬底Ag的3d电子信号逐渐减弱,在此能带区域出现两个新的谱峰,这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加,在结合能为1.51和9.20 eV处又出现了两个谱峰,它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加,上述四个谱峰的强度逐渐增加,其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果,酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计 关键词： 酞菁铜 紫外光电子谱 吸附电子态 密度泛函理论     

A shortcut for determining growth mode

Thin and thick films of iron phthalocyanine （FePc） molecules are deposited on a Ag （110） surface. The nature of the FePc growth and the interaction with the substrate have been studied by X-ray photoelectron spectroscopy （XPS）. All of the core level spectra exhibit rigid shifts towards lower binding energies following the deposition of the organic films, each by a different magnitude. A greater change and a larger shift in the Fe2p level as compared to Cls core level reveals that the adsorbate interacts with the substrate mainly via the Fe atom, located at the center of the molecule. An increase/decrease in the intensity of C1 s/Ag3d level is found to be exponentially linked to the overlayer molecular coverage. Finally, the so- called growth/decay curve indicates that FePc thin films initially develop following the FM growth mode and then transform to SK mode, resulting in 3D island aggregation.     

Ag(110)表面吸附酞菁铜分子的紫外光电子谱研究

用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附，随着酞菁铜分子覆盖度增加，衬底Ag的3d电子信号逐渐减弱，在此能带区域出现两个新的谱峰，这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加，在结合能为1.51和9.20 eV处又出现了两个谱峰，它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加，上述四个谱峰的强度逐渐增加，其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果，酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计     

Interfacial electronic structure at a metal–phthalocyanine/graphene interface:Copper–phthalocyanine versus iron–phthalocyanine

The energy level alignment of CuPc and FePc on single-layer graphene/Ni(111)(SLG/Ni)substrate was investigated by using ultraviolet and X-ray photoelectron spectroscopy(UPS and XPS).The highest occupied molecular orbitals(HOMOs)in a thick layer of CuPc and FePc lie at 1.04 eV and 0.90 eV,respectively,below the Fermi level of the SLG/Ni substrate.Weak adsorbate–substrate interaction leads to negligible interfacial dipole at the CuPc/SLG/Ni interface,while a large interfacial dipole(0.20 eV)was observed in the case of FePc/SLG/Ni interface,due to strong adsorbate–substrate coupling.In addition,a new interfacial electronic feature was observed for the first time in the case of FePc on SLG/Ni substrate.This interfacial state can be attributed to a charge transfer from the SLG/Ni substrate to unoccupied orbitals of FePc.