Yeliang Wang

Technical Institute of Physics and Chemistry, Peping, Beijing, China

Are you Yeliang Wang?

Claim your profile

Publications (26)117.22 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Based on first-principles calculations, we designed for the first time a boron-kagome-based two-dimensional MgB6 crystal, in which two boron kagome layers sandwich a triangular magnesium layer. The two-dimensional lattice is metallic with several bands across the Fermi level, and among them a Dirac point appears at the K point of the first Brillouin zone. This metal-stabilized boron kagome system displays electron-phonon coupling, with a superconductivity critical transition temperature of 4.7 K, and thus it is another possible superconducting Mg-B compound besides MgB2. Furthermore, the proposed 2D MgB6 can also be used for hydrogen storage after decoration with Ca. Up to five H2 molecules can be attracted by one Ca with an average binding energy of 0.225 eV. The unique properties of 2D MgB6 will spur broad interest in nanoscience and technology.
    Physical chemistry chemical physics : PCCP. 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Germanene, a one-atom-thick Ge layer with a honeycomb structure is prepared in an ultra-high vacuum system by deposition of Ge on Pt(111) at room temperature followed by annealing at 600—750 K for 30 min.
    ChemInform 09/2014; 45(40).
  • [Show abstract] [Hide abstract]
    ABSTRACT: We review our achievements in exploring the high resolution imaging of scanning tunneling microscopy (STM) on the surface and adsorbates in a ultra-high vacuum system, by modifying the STM tip or introducing a decoupled layer onto the substrate. With an ultra-sharp tip, the highest resolution of Si(1 1 1)-7 × 7 reconstruction can be achieved, in which all the rest atoms and adatoms are observed simultaneously with high contrast. Further functionalization of STM tips can realize selective imaging of inherent molecular states. The electronic states of perylene and metal–phthalocyanine molecules are resolved with special decorated tips on metal substrates at low temperature. Moreover, we present two kinds of buffer layer: an organic molecular layer and epitaxially grown graphene to decouple the molecular electronic structure from the influence of the underlying metallic substrate and allow the direct imaging of the intrinsic orbitals of the adsorbed molecules. Theoretical calculations and STM simulations, based on first-principle density function theory, are performed in order to understand and verify the mechanism of high-resolution images. We propose that our results provide impactful routes to pursue the goal of higher resolution, more detailed information and extensive properties for future STM applications.
    Journal of Physics Condensed Matter 09/2014; 26(39):394001. · 2.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Germanene, a 2D honeycomb lattice analogous to graphene, is fabricated on a Pt(111) surface. It exhibits a buckled configuration with a (3 × 3) superlattice coinciding with the substrate's (√19 × √19) superstructure. Covalent bonds exist throughout the germanene layer. The resulting high-quality germanene enables researchers to explore the fundamentals of germanene and its potential applications.
    Advanced Materials 05/2014; · 14.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The synthesis and structures of graphene on Ru(0001) and Pt(111), silicene on Ag(111) and Ir(111) and the honeycomb hafnium lattice on Ir(111) are reviewed. Epitaxy on a transition metal (TM) substrate is a pro­mising method to produce a variety of two dimensional (2D) atomic crystals which potentially can be used in next generation electronic devices. This method is particularly valuable in the case of producing 2D materials that do not exist in 3D forms, for instance, silicene. Based on the intensive investigations of epitaxial graphene on TM in recent years, it is known that the quality of graphene is affected by many factors, including the interaction between the 2D material overlayer and the substrate, the lattice mismatch, the nucleation density at the early stage of growth. It is found that these factors also apply to many other epitaxial 2D crystals on TM. The knowledge from the reviewed systems will shine light on the design and synthesis of new 2D crystals with novel properties.
    Small 03/2014; · 7.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Graphene (G), a two-dimensional crystal of carbon atoms arranged in the honeycomb structure, shows extraordinary physical properties such as outstanding electronic mobility, higher than silicon or copper, it is one of the strongest materials found in nature, only comparable to diamond, and at the same time one of the softest, being a unique example of a metallic membrane. We have developed a new strategy for graphene growth on metallic Ru(0001) followed by silicon-layer intercalation that not only weakens the interaction of graphene with the metal substrate but also retains its superlative properties. This G/Si/Ru architecture, produced by silicon-layer intercalation approach (SIA), was characterized and experiments have shown the high structural and electronic qualities of this new composite, and the striking differences between this material from graphene obtained by previous methods. The SIA eliminates the need for the graphene transfer and also allows for an atomic control of the distance between the graphene and the metal gate, opening doors for a new generation of graphene-based materials with tailored properties.
    Asia Communications and Photonics Conference; 11/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two-dimensional (2D) honeycomb systems made of elements with d electrons are rare. Here, we report the fabrication of a transition metal (TM) 2D layer, namely, hafnium crystalline layers on Ir(111). Experimental characterization reveals that the Hf layer has its own honeycomb lattice, morphologically identical to graphene. First-principles calculations provide evidence for directional bonding between adjacent Hf atoms, analogous to carbon atoms in graphene. Calculations further suggest that the freestanding Hf honeycomb could be ferromagnetic with magnetic moment µ/Hf = 1.46 µB. The realization and investigation of TM honeycomb layers extend the scope of 2D structures and could bring about novel properties for technological applications.
    Nano Letters 09/2013; · 13.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report on the change of structural and electronic properties while depositing Hf atoms onto the graphene epitaxially grown on Ir(111) substrate. We find that the Hf atoms intercalate between the graphene and its iridium host. This intercalation induces a new interface superstructure, as confirmed by scanning tunneling microscopy and low energy electron diffraction. Raman spectra reveal that the Hf-intercalated graphene shows the prominent features of intrinsic graphene. Our study suggests that the Hf intercalation acts as a buffer layer between the graphene and the Ir(111) substrate, restoring the graphene's intrinsic electronic properties.
    Applied Physics Letters 03/2013; 102(9). · 3.52 Impact Factor
  • Yeliang Wang, Jinhai Mao, Lei Meng, Hongjun Gao
    [Show abstract] [Hide abstract]
    ABSTRACT: Graphene is being considered as a contender as the reference material with extraordinary properties for a post-CMOS technology. The availability of high quality and large scale single crystal graphene is fundamental for it to fulfill its promise in electronic applications. Graphene is usually grown on a metallic substrate from which it has to be transferred before it can be used. However, uncontrolled shear and strain, associated with the transfer and the presence of extended domains, lead to unavoidable tearing, rendering it useless for scalable production. We propose a way to overcome this bottleneck and produce high quality, free standing graphene by intercalating Si in graphene epitaxially grown on metals, like Ru(0001) & Ir(111). This G/Si/metal architecture, produced by the silicon-layer intercalation approach (SIA), was characterized by STM/STS, Raman, and angle resolved electron photoemission spectroscopy (ARPES) and proves the high structural and electronic qualities of the new composite. The SIA eliminates the need for the graphene transfer and also allows for an atomic control of the distance between the graphene and the metal. References: 1. Jinhai Mao, Yeliang Wang, H.-J. Gao, et al., Appl. Phys. Lett. 100, 093101 (2012) (Cover). 2. Lei Meng, Yeliang Wang, H.-J. Gao, et al., Appl. Phys. Lett. 100, 083101 (2012).
    03/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The template-directed assembly of planar pentacene molecules on epitaxial graphene grown on Ru(0001) (G/Ru) has been investigated by means of low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. STM experiments find that pentacene adopts a highly selective and dispersed growth mode in the initial stage. By using DFT calculations including van der Waals interactions, we find that the configuration with pentacene adsorbed on face-centered cubic (fcc) regions of G/Ru is the most stable one, which accounts for the selective adsorption at low coverage. Moreover, at high coverage, we have successfully controlled the molecular assembly from amorphous, local ordering, to long-range order by optimizing the deposition rate and substrate temperature. Graphical abstract
    Nano Research 02/2013; 6(2). · 7.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Silicene, a two-dimensional (2D) honeycomb structure similar to graphene, has been successfully fabricated on an Ir(111) substrate. It is characterized as a (√7×√7) superstructure with respect to the substrate lattice, as revealed by low energy electron diffraction and scanning tunneling microscopy. Such a superstructure coincides with the (√3×√3) superlattice of silicene. First-principles calculations confirm that this is a (√3×√3)silicene/(√7×√7)Ir(111) configuration and that it has a buckled conformation. Importantly, the calculated electron localization function shows that the silicon adlayer on the Ir(111) substrate has 2D continuity. This work provides a method to fabricate high-quality silicene and an explanation for the formation of the buckled silicene sheet.
    Nano Letters 01/2013; · 13.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The reversible control of a single spin of an atom or a molecule is of great interest in Kondo physics and a potential application in spin based electronics. Here we demonstrate that the Kondo resonance of manganese phthalocyanine molecules on a Au(111) substrate have been reversibly switched off and on via a robust route through attachment and detachment of single hydrogen atom to the magnetic core of the molecule. As further revealed by density functional theory calculations, even though the total number of electrons of the Mn ion remains almost the same in the process, gaining one single hydrogen atom leads to redistribution of charges within 3d orbitals with a reduction of the molecular spin state from S = 3/2 to S = 1 that directly contributes to the Kondo resonance disappearance. This process is reversed by a local voltage pulse or thermal annealing to desorb the hydrogen atom.
    Scientific Reports 01/2013; 3:1210. · 5.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Silicon is the most promising high capacity anode material to replace graphite for developing next generation high energy density Li-ion batteries. In this approach, patterned amorphous and microcrystalline Si thin film electrodes (a-Si and μc-Si) have been prepared by rf-sputtering and etched further by a reactive ion etching (RIE) system to form square-shape microcolumn electrodes with controllable size (5 × 5 μm width, 500 nm height, aspect ratio of width/height is 10:1) and array distance (5 μm). It has been found that the volume expansion and contraction of a-Si and μc-Si are anisotropic, about 180% along vertical direction and 40% along lateral direction. The total volume variation changes linearly with the increase of lithium insertion content up to ∼310% for a-Si and ∼300% for μc-Si. It occurs nearly reversibly. In addition, it is observed that the original square-shape Si column transforms into the dome-like appearance after lithium insertion and changes into bowl shape after lithium extraction gradually. Radial-like curved cracks are formed after 5−10 cycles and the neighboring Si columns tend to merge together when the distance of the columns is less than 1 μm.
    Journal of Power Sources 10/2012; 216:131-138. · 5.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Six types of moiré superstructures of graphene on Ir(111) with different orientations (labeled as R0, R14, R19, R23, R26 and R30) are investigated by low-energy electron diffraction, scanning tunneling microscopy and first-principles calculations. The moiré superstructure of R0 graphene has remarkable diffraction spots and deeper corrugation than that of the other superstructures. A high-order commensurate (HOC) method is applied to produce a list of all possible graphene moiré superstructures on Ir(111). Several useful structural data including the precise matrices of the moiré patterns are revealed. Density functional theory based first-principles calculations that include van der Waals interactions reveal the differences of the geometric environment and electronic structures of carbon atoms with respect to the underlying Ir(111) lattices for all the observed moiré patterns. The further calculations of electronic properties at the graphene-Ir interfaces show that the electron transfers for all superstructures are small and of the same order of magnitude, which demonstrates a weak interaction between graphene and the Ir(111) substrate, leading to the coexistence of multi-oriented moiré superstructures.
    Journal of Physics Condensed Matter 07/2012; 24(31):314214. · 2.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A key requirement for the future applicability of molecular electronics devices is a resilience of their properties to mechanical deformation. At present, however, there is no fundamental understanding of the origins of mechanical properties of molecular films. Here we use quinacridone, which possesses flexible carbon side chains, as a model molecular system to address this issue. Eight molecular configurations with different molecular coverage are identified by scanning tunneling microscopy. Theoretical calculations reveal quantitatively the roles of different molecule-molecule and molecule-substrate interactions and predict the observed sequence of configurations. Remarkably, we find that a single Young's modulus applies for all configurations, the magnitude of which is controlled by side chain length, suggesting a versatile avenue for tuning not only the physical and chemical properties of molecular films but also their elastic properties.
    Nano Letters 03/2012; 12(3):1229-34. · 13.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report on the structural and electronic properties in the heterostructure of graphene/silicon/Ir(111). A (√19 × √19)R23.41° superstructure is confirmed by low energy electron diffraction and scanning tunneling microscopy and its formation is ascribed to silicon intercalation at the interface between the graphene and the Ir(111) substrate. The dI/dV measurements indicate that the interaction between graphene and Ir is effectively decoupled after silicon intercalation. Raman spectroscopy also reveals the vibrational states of graphene, G peak and 2D peak, which further demonstrates that the silicon-buffered graphene behaves more like intrinsic graphene.
    Applied Physics Letters 02/2012; 100(8). · 3.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The self-assemble behavior of prochiral species and the induced high-order chirality by 2D confinement on solid surfaces, including (1) QA16C molecules on a Au(111) surface and (2) molecule-metallic (TPA-Fe) complex on Cu(110) as well as their transferring process will be presented. Initial stages of a chiral phase transition in the molecule monolayer on metal surfaces were investigated by scanning tunneling microscopy (STM) at submolecular resolution. The prochiral QA16C molecules form a homochiral lamella phase at low coverages upon adsorption. A transition to a racemate lattice is observed with increasing coverage. Enantiomers of a homochiral lamella line become specifically substituted by opposite enantiomers such that a heterochiral structure evolves. A ``chiral replacement'' model is proposed for the transition: enantiomers replace QA molecules in enantiopure phase, leading to racemic one. Our findings are significant for the understanding and control of chiral phase transitions in related molecular systems like liquid crystals.
    02/2012;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Direct imaging of the intrinsic electronic structure at high resolution is of both fundamental and technological importance for investigating molecular interaction and mechanisms. Metallic or semiconducting materials are commonly used as substrates for molecular adsorption. Generally, the strong interactions between molecules and these substrates significantly change the intrinsic electronic and geometric structures of the adsorbed molecules. In order to overcome this problem, much effort has been made by passivating substrates with various buffer layers, for instance, thin organic films, NaCl, and oxides. We demonstrate the graphene grown epitaxially on Ru(0001) can be used as a buffer layer to study the intrinsic electronic properties of adsorbed molecules. The intrinsic molecular orbitals of C60, pentacene and perylene-3,4,9,10-tetracarboxylic dianhydride molecules were imaged by scanning tunneling microscope (STM). High resolution STM images of the molecules reveal that the graphene layer decouples the individual molecules electronically from the metallic substrate, which is also verified by density functional theory calculations.
    02/2012;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Understanding structures and mechanisms of single molecular motors on solid surfaces is of critical importance for nanoscale engineering and bottom-up construction of complex devices at single molecular scale. In this chapter, two different kinds of single molecular motors at surfaces are studied with scanning tunneling microscopy (STM) technique. We discuss the structural and conductance transitions of one H2 rotaxane molecule at the sub-rotaxane scale, and then present a molecular rotor with a fixed off-center axis formed by chemical bonding on Au(111) substrate. These results represent important advances in single molecular-based machines and devices.
    Atomic Scale Interconnection Machines, Advances in Atom and Single Molecule Machines. ISBN 978-3-642-28171-6. Springer-Verlag Berlin Heidelberg, 2012, p. 225. 01/2012;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We develop a strategy for graphene growth on Ru(0001) followed by silicon-layer intercalation that not only weakens the interaction of graphene with the metal substrate but also retains its superlative properties. This G/Si/Ru architecture, produced by silicon-layer intercalation approach (SIA), was characterized by scanning tunneling microscopy/spectroscopy and angle resolved electron photoemission spectroscopy. These experiments show high structural and electronic qualities of this new composite. The SIA allows for an atomic control of the distance between the graphene and the metal substrate that can be used as a top gate. Our results show potential for the next generation of graphene-based materials with tailored properties.
    Applied Physics Letters 12/2011; 100(9). · 3.52 Impact Factor

Publication Stats

104 Citations
117.22 Total Impact Points

Institutions

  • 2011–2014
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China
  • 2009–2013
    • Northeast Institute of Geography and Agroecology
      • Institute of Physics
      Beijing, Beijing Shi, China