| 1. |
- Andersen, Jesper N, et al.
(författare)
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Strong Phonon Replicas in Be 1 s Photoemission Spectra
- 2001
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Ingår i: Physical Review Letters. - 1079-7114. ; 86:19, s. 4398-4401
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Tidskriftsartikel (refereegranskat)abstract
- The Be 1s core level photoemission line from metallic Be is shown to contain unexpected internal fine structure. We argue that this fine structure is caused by intrinsic excitation of a narrow band of optical phonons in the 1s photoemission process. The general importance of the present results for high resolution core level photoemission investigations of metals is pointed out.
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| 2. |
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| 3. |
- Glans, P.-A., et al.
(författare)
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Assignment of the surface core-level shifts to the surface layers of Be(101¯0)
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 70:3
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Tidskriftsartikel (refereegranskat)abstract
- Photoemission studies and layer resolved Korringa-Kohn-Rostoker (KKR) multiple scattering calculations are used to find the assignment of the surface core-level shifts to the top layers of the Be(1010) surface. Striking similarities between experimental and calculated data make it possible to assign the largest shift to layer two, the second largest shift to layers three and four, and the smallest shift to layer one.
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| 4. |
- Johansson, Leif, et al.
(författare)
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Changes induced in the surface electronic structure of Be(0001) after Si adsorption
- 2002
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Ingår i: Surface Review and Letters. - 0218-625X. ; 9:2, s. 687-691
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Konferensbidrag (refereegranskat)abstract
- A study of effects induced in the Be 1s core level spectrum and in the surface band structure after Si adsorption on Be(0001) is reported. The changes in the Be 1s spectrum are quite dramatic. The number of resolvable surface components and the magnitude of the shifts do decrease and the relative intensities of the shifted components are drastically different compared to the clean surface. The surface band structure is also strongly affected after Si adsorption and annealing. At G the surface state is found to move down from 2.8 to 4.1 eV. The band also splits at around 0.5 Å-1 along both the G-K and G-M directions. At M and beyond K only one surface state is observed in the band gap instead of the two for the clean surface. Our findings indicate that a fairly small amount of Si in the outer atomic layers strongly modifies the electronic properties of these layers.
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| 5. |
- Johansson, Leif, et al.
(författare)
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The surface band structure of Li/Be(10(1)over-bar0)
- 2002
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Ingår i: Surface review and letters. - 0218-625X. ; 9:3-4, s. 1493-1496
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Tidskriftsartikel (refereegranskat)abstract
- A photoemision study of the surface states on Be(10 (1) over bar0) after Li adsorption at room temperature is reported. The surface band structure was mapped along four high symmetry directions of the SBZ. Fairly large shifts in the surface band locations were obtained but all surface states observed experimentally after Li adsorption were found to correspond to Be-derived states and no Li-derived surface states could be identified. The surface state bands located close to the Fermi level (E-F) were found to be affected the most and it is suggested that one surface state band which on the clean surface is located above E-F is pulled down below E-F after Li adsorption.
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| 6. |
- Kihlgren, T, et al.
(författare)
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Narrow photoemission lines from graphite valence states
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:23
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Tidskriftsartikel (refereegranskat)abstract
- Valence-band photoelectron angular distributions, measured in the photon energy range 20-150 eV, are obtained from crystalline graphite overlayers prepared by heating SiC(0001) and from a graphite natural single crystal. The dispersion of the valence bands for the overlayers agrees well with that of the single crystal. The valence electrons have binding energies, which agree with LDA calculations if the calculated binding energies are multiplied by a factor of 1.13. The upper sigma state at Gamma and states near the Fermi level at the zone corners give quite narrow emission lines. Since the widths are on par with that of the C 1s level the lines are of interest as an alternative to the core line when graphite is used as substrate for adsorption or absorption studies.
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| 7. |
- Schiessling, J, et al.
(författare)
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Origin of molecular orbital splitting of C-60 on Al(110)
- 2004
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Ingår i: Journal of Physics: Condensed Matter. - 1361-648X. ; 16:36, s. 407-414
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the C-60 monolayer on Al(l 10) with angle-dependent photoelectron spectroscopy. We find that orbital components have different angular distributions. Calculations of cross sections of the highest occupied molecular orbital components for free, oriented C-60 are found to describe the experimental data quite well. The observed band splitting is attributed to intramolecular electronic correlations, due to the different coupling of the orbital components to the substrate conduction band.
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| 8. |
- Schiessling, J, et al.
(författare)
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Polarization-dependent angular photoelectron distribution of solid C-60
- 2003
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121 .- 1550-235X. ; 68:20
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Tidskriftsartikel (refereegranskat)abstract
- We present angle- and polarization-dependent photoelectron spectra of solid C-60 recorded over a large range of emission angles. The bands derived from the three highest molecular orbitals are very similar in their angular distribution and show a strong dependence on both light polarization direction and sample orientation. We show that a molecular emission pattern modified by solid-state effects accounts for the observations.
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| 9. |
- Thiagarajan, Balasubramanian, et al.
(författare)
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Narrow UV photoemission lines from graphite
- 2002
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Ingår i: 7th International Conference on Nanometer-Scale Science andTechnology and 21st European Conference on Surface Science.
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Konferensbidrag (refereegranskat)abstract
- Stimulated by the recent observation by LEED that well ordered graphite overlayers may be prepared by heating SiC crystals [1] we have used LEED, STM and UPS (hv = 20-140 eV) to study such layers and compared the photoemission spectra to those we obtain from a natural single crystal. Two results are of particular interest. One is that the overlayers give spectra having a quality well on par with those from the natural crystal. This means that the overlayers can be attractive as an alternative to natural crystals, which are inconveniently small for many experiments. The other result is that there are graphite states, which give quite narrow emission lines. One is due to the upper σ state at Γ and another to states near the Fermi level, which for graphite means states at the zone corners. Both lines should be useful for ador absorption studies as an alternative to the C 1s core line and the σ line may provide testing ground for the current modeling of excitation lifetimes in graphite.
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| 10. |
- Uhrberg, RIG, et al.
(författare)
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Photoelectron spectroscopy study of Ag/Si(111)root 3X root 3 and the effect of additional Ag adatoms
- 2002
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 65:8
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution core-level spectroscopy has been applied to the Ag/Si(111)root3xroot3 surface. The Si 2p line shape is found to depend critically on the presence of additional Ag adatoms on the surface. A significant broadening caused by the surplus of Ag atoms could be eliminated by careful annealing. The resulting Si 2p spectra are significantly sharper than any published data for this or other Si based surface systems. Two major surface components are identified for the root3xroot3 surface, which find a natural explanation in terms of the honeycomb-chained-trimer model. A small but characteristic contribution to the Si 2p spectrum of the Ag/root3xroot3 surface is tentatively assigned to defects.
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