| 1. |
- Agui, A., et al.
(author)
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Direct observation of interface effects of thin AlAs(100) layers buried in GaAs
- 2000
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In: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 166:1-4, s. 309-312
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Journal article (peer-reviewed)abstract
- A study of the electronic structure of ultrathin AlAs layers buried in GaAs(100) and their interfaces is presented. Al L2,3 soft-X-ray-emission (SXE) spectra from the AlAs layers were measured. The spectra show distinct thickness-dependent features, which are reproduced using ab initio calculations.
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| 2. |
- Aryasetiawan, F., et al.
(author)
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Energy loss spectra and plasmon dispersions in alkali metals : Negative plasmon dispersion in Cs
- 1994
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 73:12, s. 1679-1682
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Journal article (peer-reviewed)abstract
- We present ab initio calculations of the energy loss spectra and plasmon dispersions of the alkali metals Na, K, Rb, and Cs within the random phase approximation, including band structure effects and core electrons as well as local field effects, due to inhomogeneity in the induced charge density. Band structure effects are found to cause a negative dispersion in Cs.
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| 3. |
- Aryasetiawan, F., et al.
(author)
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GW spectral functions of Gd and NiO
- 1996
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In: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 54:8, s. 5353-5357
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Journal article (peer-reviewed)abstract
- The spectral functions of highly correlated systems Gd and NiO have been calculated within the GW approximation. In the case of Gd, satellites are found at the positions of the experimental main peaks. However, some quasiparticle weight remains at the local density eigenvalue but its weight is unusually small (0.3). In NiO, satellite structure is observed at around -10 eV when starting from the local density Hamiltonian. It is found, however, that the satellite intensity is reduced towards self-consistency and almost disappears. © 1996 The American Physical Society.
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| 4. |
- Aryasetiawan, F., et al.
(author)
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Multiple Plasmon Satellites in Na and Al Spectral Functions from Ab Initio Cumulant Expansion
- 1996
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 77:11, s. 2268-2271
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Journal article (peer-reviewed)abstract
- The valence photoemission spectra of alkali metals exhibit multiple plasmon satellite structure. The calculated spectral functions within the GW approximation show only one plasmon satellite at too large binding energy. In this Letter we use the cumulant expansion approach to obtain the spectral functions of Na and Al from ab initio calculations including the effects of band structure. The GW spectral functions are dramatically improved and the positions of the multiple plasmon satellites are in very good agreement with experiment while their intensities cannot be explained from intrinsic effects only.
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| 5. |
- Chauhan, H. S., et al.
(author)
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Direct- and inverse-photoemission investigations of the electronic structure of Cd(0001)
- 1993
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In: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 48:7, s. 4729-4734
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Journal article (peer-reviewed)abstract
- Photoemission and inverse angle-resolved photoemission spectra are presented for Cd(0001). The data are interpreted in terms of interband transitions, density-of-states effects, and excitations of surface states.
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| 6. |
- Gunnarsson, O., et al.
(author)
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Information from photoemission spectral weights and shapes
- 2001
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In: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier. - 0368-2048 .- 1873-2526. ; 117-118, s. 1-11
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Journal article (peer-reviewed)abstract
- Photoemission line shapes can be used to extract important information about ground-state and low-energy properties. This is illustrated for the electron–phonon interaction in C60 molecules, the occupancy and hybridization of the 4f-level in Ce compounds, the effect of the Cu–O network on core-level photoemission in cuprates and the properties of one-dimensional conductors.
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| 7. |
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| 8. |
- Kanski, Janusz, 1946, et al.
(author)
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Electronic structure of (Ga,Mn)As revisited
- 2017
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In: New Journal of Physics. - : Institute of Physics (IOP). - 1367-2630. ; 19:2, s. 1-8
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Journal article (peer-reviewed)abstract
- The detailed nature of electronic states mediating ferromagnetic coupling in dilute magnetic semiconductors, specifically (Ga,Mn)As, has been an issue of long debate. Two confronting models have been discussed emphasizing host band vs. impurity band carriers. Using angle resolved photoemission we show that the electronic structure of the (Ga,Mn)As system is significantly modified from that of GaAs throughout the valence band. Close to the Fermi energy, the presence of Mn induces a strong mixing of the bulk bands of GaAs, which results in the appearance of a highly dispersive band in the gap region of GaAs.For Mn concentrations above 1% the band reaches the Fermi level, and can thus host the delocalized holes needed for ferromagnetic coupling. Overall, our data provide a firm evidence of delocalized carriers belonging to the modified host valence band.
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| 9. |
- Karlsson, Krister, 1961-, et al.
(author)
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A many-body approach to spin-wave excitations in itinerant magnetic systems
- 2000
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In: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 12:34, s. 7617-7631
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Journal article (peer-reviewed)abstract
- Using a recently developed Green's function formalism, we have calculated the spin-wave spectra and dispersions in Ni and Fe. For Ni(100), the dispersion exhibits two branches as observed experimentally. The calculated higher optical branch is found to be too high in energy when the standard local density approximation band-structure is used but a very good agreement with the measured dispersion is obtained when the exchange splitting is reduced, to correspond to the experimental value of the exchange splitting. We also found a double branch along Ni(111) which is not observed experimentally. For Fe, the calculated dispersion surprisingly exposes a gap midway along Γ-N in disagreement with experimental data. However, an analysis of the temperature-dependent magnetization has predicted a similar gap at the same wave vector, supporting the present calculations.
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| 10. |
- Karlsson, Krister, 1961-, et al.
(author)
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Chemical shifts for monovalent, divalent and trivalent Cu compounds
- 1992
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In: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 4:3, s. 895-909
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Journal article (peer-reviewed)abstract
- The authors study the chemical shift of the Cu 2p core level for Cu 2O, CuO and NaCuO2, where Cu is formally monovalent, divalent and trivalent, respectively. They find that the binding energy increases with the valence, as expected, although the variation in the number of 3d electrons is small and the trivalent Cu atom is found to have a smaller net positive charge than the monovalent or divalent Cu. The origin of the calculated chemical shifts is analysed and the relation with the chemical valence is discussed.
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