| 1. |
- Plucinski, L, et al.
(författare)
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Resonant shake-up satellites in photoemission at the Ga 3p photothreshold in GaN
- 2005
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Ingår i: Solid State Communications. - : Elsevier BV. - 1879-2766 .- 0038-1098. ; 136:4, s. 191-195
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Tidskriftsartikel (refereegranskat)abstract
- Photoemission spectra recorded near the Ga 3p photothreshold from GaN have been found to contain satellites of the main Ga 3d emission line. The intensity of these satellites resonate at this threshold, and are associated with a 3d(8) state. The correlation energies and binding energies for the satellite multiplet have been measured for the satellite and related Auger transitions. The satellite multiplet contains additional constant binding energy features not observed in previous studies of other Ga compounds. The present results are compared with those for Gal? and GaAs.
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| 2. |
- Freelon, B., et al.
(författare)
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Low energy electronic spectroscopy of an infinite-layer cuprate : A resonant inelastic X-ray scattering study of CaCuO2
- 2010
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Ingår i: Physica. C, Superconductivity. - : Elsevier BV. - 0921-4534 .- 1873-2143. ; 470:3, s. 187-192
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Tidskriftsartikel (refereegranskat)abstract
- We report the results of Oxygen K-edge soft X-ray absorption and emission spectroscopy that was performed on an infinite-layer insulating cuprate thin film CaCuO2 Experimentally obtained spectra arc consistent with local density approximation calculations X-ray absorption spectra show a close resemblance to spectra obtained from homologous single crystal cuprates In addition to d-d excitations. X-ray emission spectra reveal the presence of Zhang-Rice singlet states in the infinite-layer CuO2 planes The question of whether the Zhang-Rice singlet features are masked by the O 2p main-band is addressed. it is possible to quantify the position of the Zhang-Rice singlet using emission intensity profiles X-ray emission is demonstrated as a tool for understanding CuO2 planar electronic correlation in the prototypical infinite-layer The energy difference, 2 0 eV, between the oxygen main-band and the Zhang-Rice singlet band is found to match values obtained theoretically using established planar electronic correlation parameters.
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| 3. |
- Glans, P. -A, et al.
(författare)
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Electronic structure of boron doped diamond : An x-ray spectroscopic study
- 2013
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:16, s. 162103-
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Tidskriftsartikel (refereegranskat)abstract
- The valence and conduction band electronic structure of boron-doped diamond has been measured using soft x-ray emission and absorption spectroscopy. The experimental results reveal p-type doping in the diamond film through the appearance of states in the band-gap. Structure distortion was observed around the doping center, while the long range order of the diamond structure remains. A chemically shifted C 1s level explains why one of the absorption features seems to appear below the valence band maximum. An excitonic feature was observed in the boron-doped diamond, similar to that observed in pure diamond, indicating that the exciton binding energy remains the same upon B-doping.
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| 4. |
- Granville, S, et al.
(författare)
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Optical conductivity and x-ray absorption and emission study of the band structure of MnN films
- 2005
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 72:20, s. 205127-
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Tidskriftsartikel (refereegranskat)abstract
- The band structure of MnN films prepared by ion assisted deposition has been investigated by optical conductivity and x-ray absorption and emission spectroscopies. X-ray diffraction and extended x-ray absorption fine structure show the films to be nanocrystalline but phase pure and exhibiting the known antiferromagnetic distorted rocksalt phase. X-ray emission spectroscopy of the N K-edge and x-ray absorption near edge spectroscopy of both the N K- and Mn L-edges are used to probe the occupied and empty densities of states, which compare well with the N(2p) and Mn(3d) partial densities of states calculated using the linearized muffin-tin orbital band structure method. A similar comparison is made between the measured optical conductivity and the calculated contribution from interband transitions. It is possible to associate the main features in the measured spectrum with corresponding ones in the calculated optical function. The major differences between calculated and measured spectra can be understood on the basis of a limited electron mean-free-path in these nanocrystalline films, which broadens the features in the joint density of states and relaxes the momentum conservation requirement. The calculated optical functions are analyzed in detail in terms of their dominant band-to-band contributions and in addition the polarization dependence is predicted. Temperature dependent conductivity measurements are also reported and show a clear metallic behavior and a weak Kondo-like low temperature anomaly.
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| 5. |
- Guo, J. -H, et al.
(författare)
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Electronic structure study of the bases in DNA duplexes by in situ photon-in/photon-out soft X-ray spectroscopy
- 2010
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048 .- 1873-2526. ; 181:2-3, s. 197-201
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Tidskriftsartikel (refereegranskat)abstract
- Understanding protein functionality is of fundamental importance in biochemistry. Soft X-ray transitions, where the core-level vacancies are filled by the valence-orbital electrons, give direct information about the chemical bonding. Soft X-ray absorption and emission study of poly(dG) -poly(dC) in aqueous solutions can elucidate the relation between the structure and functionality of proteins. We report the N K-edge soft X-ray absorption (XAS) and resonant soft X-ray emission spectroscopy (XES) to characterize the electronic structure near the Fermi level of DNA duplexes to specify the charge migration mechanism. Since N atoms are included in only bases in DNA duplexes, the XES spectra excited from N Is to unoccupied states purely extract the electronic orbital features of the bases in DNA. The fact that N atoms in different bonding environments form well-defined structure has been determined. The experimental findings provide the evidence for the charge-hopping and/or charge-transfer effects in understanding of electric conduction in DNA duplexes when electrons pass through the pi* states of DNA bases.
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| 6. |
- Krishnamurthy, S, et al.
(författare)
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Soft-x-ray spectroscopic investigation of ferromagnetic Co-doped ZnO
- 2006
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 99:8
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Tidskriftsartikel (refereegranskat)abstract
- The electronic properties of cobalt-doped ZnO were investigated through site-selective and element-sensitive x-ray-absorption spectroscopy in the vicinity of the Co L-2,L-3 edge, the oxygen K edge, and at the Zn L-3 edge. The spectroscopic measurements of the ferromagnetic cobalt-doped ZnO films appear to have additional components in the O K edge x-ray-absorption spectrum not observed in the undoped films. The observed features may derive from both hybridization with unoccupied Co 3d states and also from lattice defects such as oxygen vacancies. Only minor changes in the Zn L-3 edge spectra were observed. These observations are consistent with a polaron percolation model in which the ferromagnetic coupling is mediated by shallow donor electrons trapped in oxygen vacancies and couples the Co atoms substituted on Zn sites in the hexagonal wurtzite ZnO structure.
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| 7. |
- Learmonth, T., et al.
(författare)
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Observation of multiple Zhang-Rice excitations in a correlated solid : Resonant inelastic X-ray scattering study of Li2CuO2
- 2007
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 79:4, s. 47012-
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Tidskriftsartikel (refereegranskat)abstract
- Multiple Zhang-Rice type spectral features have been observed in resonant inelastic X-ray scattering (RIXS) from the quasi -one-dimensional cuprate charge transfer insulator Li2CuO2. The first feature appears at constant emission energy, and is associated with a Zhang-Rice singlet final state. The second is an interplaquette charge transfer excitation that results in a novel triplet Zhang-Rice -type final state. It is accompanied by the presence of a O 2p nonbonding to upper Hubbard band excitation at an energy close to that of a calculated triplet charge transfer Zhang-Rice -type excitation. The site selectivity and polarization rules associated with RIXS allows these two excitations to be distinguished.
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