Université de Fribourg

Surface science at the PEARL beamline of the Swiss Light Source

Muntwiler, Matthias ; Zhang, Jun ; Stania, Roland ; Matsui, Fumihiko ; Oberta, Peter ; Flechsig, d Uwe ; Patthey, Luc ; Quitmann, Christoph ; Glatzel, Thilo ; Widmer, Roland ; Meyer, Ernst ; Jung, Thomas A. ; Aebi, Philipp ; Fasel, Roman ; Greber, Thomas

In: Journal of Synchrotron Radiation, 2017, vol. 24, no. 1, p. 354–366

The Photo-Emission and Atomic Resolution Laboratory (PEARL) is a new soft X-ray beamline and surface science laboratory at the Swiss Light Source. PEARL is dedicated to the structural characterization of local bonding geometry at surfaces and interfaces of novel materials, in particular of molecular adsorbates, nanostructured surfaces, and surfaces of complex materials. The main experimental...

Université de Neuchâtel

Geometrical and electronic structure of Pd clusters on graphite

Bovet, M. ; Boschung, E. ; Hayoz, J. ; Pillo, Th. ; Dietler, G. ; Aebi, Philipp

In: Surface Science, 2001, vol. 473, no. 1-2, p. 17-24

Pd clusters formed by physical vapor deposition at room temperature (RT) on highly oriented pyrolytic graphite were investigated by a combination of X-ray photoelectron spectroscopy and diffraction, angle-resolved ultraviolet photoelectron spectroscopy, scanning tunneling microscopy and calculations based on the local density functional theory. Different coverages with nominally 3, 5 and 10 Å...

Université de Neuchâtel

Angle-scanned photoelectron diffraction

Osterwalder, Jürg ; Aebi, Philipp ; Naumovic, D. ; Schwaller, P. ; Kreutz, T. J. ; Schlapbach, Louis ; Abukawa, T. ; Kono, S.

In: Surface Science, 1995, vol. 331-333, no. 2, p. 1002-1014

A brief survey is given on the current state-of-the-art of this surface structural technique based on photoelectron spectroscopy, with particular emphasis on the progress that has been made recently by routinely measuring full-hemispherical intensity distributions. We limit the discussion to the photoelectron forward focusing regime, which is attained at electron kinetic energies of a few hundred...

Université de Neuchâtel

Electronic excitations in the transition metals V, Zr, Nb, Mo, and Ta

Cornaz, A. ; Erbudak, M. ; Aebi, Philipp ; Stucki, F. ; Vanini, F.

In: Physical Review B, 1987, vol. 35, no. 7, p. 3062-3068

The np core-loss spectra and the associated deexcitation processes for the transition metals V (n=3), Zr, Nb, Mo (n=4), and Ta (n=5) have been studied in low-energy electron scattering experiments in order to investigate the dependence of their nature on the principle quantum number n. For the metals with n=3 and n=4, the measurements are accounted for in...

Université de Neuchâtel

L and M edges of copper: Theory and experiment

Aebi, Philipp ; Erbudak, M. ; Vanini, F. ; Vvedensky, D. D. ; Kostorz, G.

In: Physical Review B, 1990, vol. 41, no. 17, p. 11760-11769

Characteristic electronic transitions and the associated fine structure in the near-edge region are investigated with electron-energy-loss spectroscopy for the copper L and M edges. In a single-particle scattering picture this fine structure represents the unoccupied density of states selected by the matrix elements. However, electronic processes can often complicate this simple...

Université de Neuchâtel

Complete Fermi surface mapping of Bi2Sr2CaCu2O8+x(001): Coexistence of short range antiferromagnetic correlations and metallicity in the same phase

Aebi, Philipp ; Osterwalder, Jürg ; Schwaller, P. ; Schlapbach, Louis ; Shimoda, M. ; Mochiku, T. ; Kadowaki, K.

In: Physical Review Letters, 1994, vol. 72, no. 17, p. 2757-2760

The Fermi surface of Bi2Sr2CaCu2O8+x(001) has been mapped at nearly 6000 points in k space using angle-resolved photoemission at 300 K. We observe both features that are in good agreement with the local density calculation of Massidda, Yu, and Freeman [Physica (Amsterdam) 158C, 251 (1988)] and others that are missing in the calculation....

Université de Neuchâtel

Theoretical analysis of the electronic structure of the stable and metastable c (2×2) phases of Na on Al(001): Comparison with angle-resolved ultraviolet photoemission spectra

Stampfl, C. ; Kambe, K. ; Fasel, Roman ; Aebi, Philipp ; Scheffler, M.

In: Physical Review B, 1998, vol. 57, no. 24, p. 15251-15260

Using Kohn-Sham wave functions and their energy levels obtained by density-functional-theory total-energy calculations, the electronic structure of the two c (2×2) phases of Na on Al(001) are analyzed, namely, the metastable hollow-site structure formed when adsorption takes place at low temperature, and the stable substitutional structure appearing when the substrate is heated thereafter...

Université de Neuchâtel

Electronic structure and Fermi surface of two-dimensional rare-earth silicides epitaxially grown on Si(111)

Rogero, C. ; Koitzsch, Christian ; González, M. E. ; Aebi, Philipp ; Cerdá, J. ; Martín-Gago, J. A.

In: Physical Review B, 2004, vol. 69, no. 045312, p. 1-10

The electronic structure and the Fermi surface of two-dimensional rare-earth silicides epitaxially grown on Si(111), YSi2 and GdSi2, have been studied by a combination of angle-resolved ultraviolet photoemission spectroscopy and density functional theory calculations. Both silicides present a very similar electronic structure, with two characteristic electronic bands below...

Université de Neuchâtel

Fine structure in high-resolution photoemission spectra of quasi-two-dimensional 1T-TaS2

Pillo, Th. ; Hayoz, J. ; Naumovic, D. ; Berger, Helmuth ; Perfetti, L. ; Gavioli, L. ; Taleb-Ibrahimi, A. ; Schlapbach, Louis ; Aebi, Philipp

In: Physical Review B, 2001, vol. 64, no. 245105, p. 1-4

Using high-resolution angle-resolved photoemission spectroscopy (ARPES), we examined the charge density wave (CDW) compound 1T-TaS2 as a function of the photon energy (energy range from 11 up to 33 eV) for both quasicommensurate (QC) and commensurate (C) CDW phases. While the QC-phase normal emission ARPES spectra coincide with previous results, normal emission spectra of the C...

Université de Neuchâtel

Interplay between electron-electron interaction and electron-phonon coupling near the Fermi surface of 1T-TaS2

Pillo, Th. ; Hayoz, J. ; Berger, Helmuth ; Fasel, Roman ; Schlapbach, Louis ; Aebi, Philipp

In: Physical Review B, 2000, vol. 62, no. 7, p. 4277-4287

We present a detailed high-resolution angle-resolved photoemission study of the electronic band structure of the room-temperature quasicommensurate charge-density-wave phase of 1T-TaS2. In particular, we show that no crossings of the Fermi level are visible in the complete Brillouin zone, indicating that an electron-electron correlation-induced pseudogap in the Ta 5d...