Modification of surface-state dispersion upon Xe adsorption: A scanning tunneling microscope study

Park, Ji Yong; Ham, Ungdon; Kahng, Se-Jong; Kuk, Young; Miyake, Koji; Hata, Kenji; Shigekawa, Hidemi

doi:10.1103/physrevb.62.r16341

Cited by 52 publications

(54 citation statements)

References 32 publications

(30 reference statements)

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“…Scanning tunneling microscopy (STM) is a powerful tool to probe these states, which are confined in perpendicular direction to the surfaces. Relevant and quantitative information can * manuela.garnica@tum.de be extracted from the study of the evolution and modification of these states by the adsorption of gases [14][15][16], molecules [17][18][19][20][21][22], ionic films [23], and 2D honeycomb layers [24][25][26]. On the other hand, scanning tunneling spectroscopy (STS) has been exploited to investigate the unoccupied states of ultrathin layers on metals, in particular, the image potential states [24,[27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Comparative study of the interfaces of graphene and hexagonal boron nitride with silver

et al. 2016

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2016). Comparative study of the interfaces of graphene and hexagonal boron nitride with silver. Physical Review B, 94(15), [155431]. DOI: 10.1103/PhysRevB.94.155431 PHYSICAL REVIEW B 94, 155431 (2016 Comparative study of the interfaces of graphene and hexagonal boron nitride with silver Silver opens up interesting perspectives in the fabrication of complex systems based on heteroepitaxial layers after the growth of a silicene layer on its (111) face has been proposed. In this work we explore different synthesis methods of hexagonal boron nitride (h-BN) and graphene sheets on silver. The resulting layers have been examined by high-resolution scanning tunneling microscopy. A comparison of the interfacial electronic band structure upon growth of the distinct two-dimensional (2D) layers has been performed by scanning tunneling spectroscopy and complementary first-principle calculations. We demonstrate that the adsorption of the 2D layers has an effect on the binding energy of the Shockley state and the surface potential by lowering the local work function. These effects are larger in the case of graphene where the surface state of Ag (111) is depopulated due to charge transfer to the graphene. Furthermore, we show that the electronic properties of the h-BN/silver system can be tuned by employing different thicknesses of silver ranging from a few monolayers on Cu(111) to the single crystal Ag substrate.

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Section: Introductionmentioning

confidence: 99%

Comparative study of the interfaces of graphene and hexagonal boron nitride with silver

et al. 2016

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“…As have been observed, for example, on the (111) surface of noble metals, standing wave, the long-range modulation of LDOS, originates from the quantum interference of low-dimensional free electrons. 16,17 However, this is the first result that demonstrates the formation of an anisotropic 2D electronic structure in the SAM of an organic material, reflecting the characteristics of the molecular arrangement.The 10-fold difference in the effective masses is attributed to the anisotropy of the molecular interactions in the SAM; that is, the interaction along the molecular rows in the [110] direction is stronger than the interaction between the molecular rows. In fact, although it is not shown here, the p(2 × 4) arrangement exhibited some phase defects formed by the substitution of a molecular row of one chirality with a molecular row of the other chirality (appearance of SSS or RRR ordering instead of SRS or RSR as in Figure 1b).…”

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confidence: 74%

Anisotropic Free-Electron-Like Dispersions and Standing Waves Realized in Self-Assembled Monolayers of Glycine on Cu(100)

et al. 2007

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Knowledge and control of the self-organization of materials are the essential foundations not only for understanding the mechanism of the phenomenon but also for the development of functional materials and devices for practical applications. In fact, among the recent developments in nanoscale science and technology, the realization of new functions via self-organization is the basis of many brilliant innovations and is one of the main goals of researchers. Efficient use of the multifold characteristics of organic materials plays important roles. [1][2][3][4][5][6][7][8][9][10][11][12] The formation of nanostructures is achieved, in general, by controlling the direct and indirect interactions between building blocks, originating from, for example, electronic and conformational structures, strains, and chemical reactions. Recently, a selective supramolecular assembly of adsorbed molecules, for example, has been successfully produced through the chemical modification of functional groups. 1 For the further advance of the nanostructurebased functional devices, the understanding and control of the electronic properties of self-organized structures based on such a modification of interactions are key factors for success.Here, we demonstrate a two-dimensional (2D) anisotropic electronic structure produced through the formation of a selfassembled monolayer (SAM) of glycine molecules on a Cu(100) surface. A standing wave originating from the 2D electronic structure was visualized, for the first time, for the SAM of organic molecules, and the anisotropic dispersion relations reflecting the structure of the SAM were obtained.Glycine is the simplest amino acid and does not have any active functional groups except for the carboxyl and amino groups, which are common to all amino acids, and one of the fundamental components of biological molecules such as proteins and peptides. Glycine molecules are evaporated in a neutral form (NH 2 CH 2 -COOH). When the substrate is maintained at room temperature (RT), the hydrogen atom in the carboxyl group is removed from the surface and glycine molecules are adsorbed in a glycinate form (NH 2 CH 2 COO -). 12,13 The two oxygen atoms in the carboxylate group and the nitrogen atom in the amino group, which are located on the top sites of Cu(100), are bonded to the Cu atoms, where the carboxyl and amino groups are negatively and positively polarized, respectively. Among the amino acids, glycine is the only molecule that does not have chirality, but enantiomeric isomers are observed on the Cu surface depending on the directional relationship of the two groups in the adsorbed form, as schematically shown in Figure 1c. The adsorption properties of this system are well characterized, indicating the importance of this material for understanding and application of the basic mechanism of the self-organization of a polarized molecule with chirality.In addition to sample preparation, scanning tunneling microscopy and spectroscopy (STM/STS) measurements were performed under ultrahigh vacuum conditions ...

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“…Their overall shape is similar to those presented in the previous theoretical studies 38,40 as well as to the data obtained in a number of experiments. [41][42][43] The step-shaped onsets of the surface state can be easily observed at bias voltages of the surface state is reproduced only for a value of the lattice constant α 2 hex optimized within the PBE + D2 approach. This appears to be in contrast with previous theoretical results based on a Perdew-Wang (PW91) parametrization, where setting the α hex to an experimental value was needed to obtain the quantitatively correct data.…”

Section: A Cu(111) Substrate: N-type Doping Of Graphenementioning

confidence: 99%

Fingerprints of Dirac points in first-principles calculations of scanning tunneling spectra of graphene on a metal substrate

Sławińska

Zasada

2011

Phys. Rev. B

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Graphene physisorbed on a metal has its characteristic Dirac cones preserved in the band structure, but the Fermi level of the system is shifted due to the interaction with the substrate. Based on density functional calculations with van der Waals corrections, we present a method to determine the position of the Dirac point with respect to the Fermi level from the measured scanning tunneling spectra (STS). It has been demonstrated that the dips in both simulated local density of states and in the observed dI/dV profiles are indeed the fingerprints of the Dirac points. The type and the level of doping can be then inferred directly from the STS data without any additional experimental technique. Test calculations of graphene on a Cu(111) substrate have shown that the predicted position of the Dirac point is in close proximity to the experimental value reported in the recent studies. Moreover, simulations for graphene on a Pt(111) surface allow us to explain the apparent contradictions in the state-of-the-art experimental works.

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Modification of surface-state dispersion upon Xe adsorption: A scanning tunneling microscope study

Cited by 52 publications

References 32 publications

Comparative study of the interfaces of graphene and hexagonal boron nitride with silver

Comparative study of the interfaces of graphene and hexagonal boron nitride with silver

Anisotropic Free-Electron-Like Dispersions and Standing Waves Realized in Self-Assembled Monolayers of Glycine on Cu(100)

Fingerprints of Dirac points in first-principles calculations of scanning tunneling spectra of graphene on a metal substrate

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