Transitions conserving parallel momentum in photoemission from the (111) face of copper

Gartland, P.; Slagsvold, B.J.

doi:10.1103/physrevb.12.4047

Cited by 374 publications

(112 citation statements)

References 27 publications

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“…We apply our method to s-p surface-state electrons on the 22 3 p reconstructed Au(111) surface [3]. Noble-metal surface-state electrons behave as nearly free 2D electron gas with parabolic dispersion [4]. On Au(111) we find a band edge energy E ÿ ÿ510 10 meV and an effective mass of m 0:27 0:01 m e , in agreement with Refs.…”

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confidence: 71%

Imaging of Electron Potential Landscapes on Au(111)

2002

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The Hohenberg-Kohn theorem states that the ground state electron density completely determines the external potential acting on an electron system. Inspired by this fundamental theorem, we developed a novel approach to map directly the electron potential in surface systems: linear response theory applied to the total electron density as measured with scanning tunneling microscopy determines the external potential. Potential imaging is demonstrated for the s-p derived surface state on Au(111), where the ''herringbone'' reconstruction induces a periodic potential modulation, the details of which are revealed by our technique.

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supporting

confidence: 71%

Imaging of Electron Potential Landscapes on Au(111)

2002

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“…As a result of the termination of the crystal at the surface an occupied Shockley-type surface state appears in this gap, which represents a quasi-two-dimensional electron gas. The existence of these states has been proposed by Shockley [4] and was experu Fax: +49-631/205-3903, E-mail: MKBAUER@PHYSIK.UNI-KL.DE imentally identified first by Gartland and Slagsvold [5]. The localization of this state right at the surface makes it in general an ideal probe for the determination of surface conditions and properties [6].…”

Section: Introductionmentioning

confidence: 99%

Electronic surface structure of n -ML Ag/Cu(111) and Cs/ n -ML Ag/Cu(111) as investigated by 2PPE and STS

Wessendorf

Wiemann

Bauer

et al. 2004

Applied Physics A: Materials Science & Processing

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We investigated the electronic structure of epitaxially grown silver films on Cu(111) with and without adsorption of cesium by means of scanning tunneling spectroscopy and two-photon photoemission. This system has been chosen as a model system to engineer and measure the dynamics of charge-transfer processes between an adsorbate and a heterogeneous substrate. Special emphasis has been laid on the investigation of the energy shift of the Shockley-type surface state and an excited cesium resonance as a function of Ag film thickness. For the cesium resonance we observe an increase in line width with increasing layer thickness.PACS 68.37.Ef; 68.55.Jk; IntroductionThe dynamics of excited electrons on adsorbatecovered surfaces determines many surface processes, in particular photon-and electron-stimulated reactions. The efficiency of these reaction mechanisms depends in a crucial way on the lifetime of intermediate electronic states. Recently, it has been demonstrated experimentally and theoretically that adsorbed alkali atoms on noble metals are an ideal model system to study the dynamics of charge-transfer processes between surface and chemisorbed adsorbates [1][2][3]. In a theoretical work, Borisov et al. showed that the substrate band structure is the most important parameter for the specific relaxation dynamics of the excited alkali state [3]. This knowledge opens the possibility to modify the adsorbate-substrate coupling and, hence, the dynamics of charge-transfer processes by the use of a properly adjusted heterogeneous substrate. Metallic thin-film overlayers, such as Co/Cu(111) or Ag/Cu(111), are ideal model substrates for this kind of study.Cu(111) has a gap of ∼ 5 eV around the Fermi level in the projected band structure at the Γ -point (L 2 -L 1 gap). As a result of the termination of the crystal at the surface an occupied Shockley-type surface state appears in this gap, which represents a quasi-two-dimensional electron gas. The existence of these states has been proposed by Shockley [4] and was exper- imentally identified first by Gartland and Slagsvold [5]. The localization of this state right at the surface makes it in general an ideal probe for the determination of surface conditions and properties [6]. In the few-monolayer (ML) regime a metallic overlayer of e.g. Na [7], Pd [8] or Ag [9] influences the binding energy of the surface state of Cu(111). For thicker films (more than 10 ML) discrete quantum well states (QWS) appear in the band gap, which have been observed by means of photoemission [10]. The energy of these states is determined by the film thickness and can be tuned quasi-continuously. Therefore, by adjusting the energetic position of relevant electronic states by means of metallic thin-film overlayers one has the potential to engineer the dynamics of charge-transfer processes on adsorbate-covered surfaces and, hence, can modify specific properties of chemical surface reactions such as efficiency and reaction channels.The paper is organized as follows: in the first part we presen...

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“…Noble-metal surface states have been the focus of experimental interest for over two decades, from their initial observation by angle-resolved photoemission spectroscopy by Gartland and Slagsvold [12] through to recent studies of defect scattering and lateral confinement on surface nanostructures [176][177][178][179][180]. The insight obtained from photoelectron spectroscopy has been reviewed in the preceding Section 3.…”

Section: Scanning Tunneling Techniquesmentioning

confidence: 99%

“…The maximum of the probability density for the first image-potential state is several Angstroms away from the surface and increases quadratically with the quantum number n. Intrinsic surface states on the other hand have their maximum close to the surface and are often classified according to the authors of the respective original models as Tamm [9,10] and Shockley [11] states. Even though the distinction is not clear in all cases, more localized surface states are usually called Tamm states, whereas Shockley states show a strong free-electron-like dispersion [12]. The different types of surface states allow to study the effect of weak or strong coupling to the underlying bulk bands.…”

Section: Introductionmentioning

confidence: 99%