| 1. |
- Sing, M., et al.
(författare)
-
Electronic structure studies of pressure-polymerized C60
- 1999
-
Ingår i: Synthetic Metals vol. 103. - : Elsevier B.V.. ; 103:1-3, s. 2454-2455
-
Konferensbidrag (refereegranskat)abstract
- We have investigated the electronic structure of one and two-dimensional C60 polymers with regard to both their low-lying excitations and C 1s excitation spectra by means of electron energy-loss spectroscopy in transmission. We compare the results with those for pristine C60. In general, the spectra for the polymers resemble those for pristine C60 but show a broadening due to both the lowering of the symmetry and the increased intermolecular overlap. This is also reflected by a reduction of the optical gap in comparison with pristine C60.
|
|
| 2. |
- Pichler, T, et al.
(författare)
-
Proof for trivalent Sc ions in Sc-2 @ C-84 from high-energy spectroscopy
- 2000
-
Ingår i: PHYSICAL REVIEW B. - : AMERICAN PHYSICAL SOC. - 0163-1829. ; 62:19, s. 13196-13201
-
Tidskriftsartikel (refereegranskat)abstract
- The electronic structure and the valency of the Sc ions in the endohedral dimetallofullerene Sc-2 @ C-84 with D-2d symmetry are probed using high-energy spectroscopy. Comparison of the Sc 2p --> 3d x-ray-absorption spectrum with calculated ionic multiplet
|
|
| 3. |
- Aristov, V. Yu., et al.
(författare)
-
Electronic properties of potassium-doped FePc
- 2010
-
Ingår i: Organic Electronics. - : Elsevier BV. - 1566-1199. ; 11:8, s. 1461-1468
-
Tidskriftsartikel (refereegranskat)abstract
- The evolution of electronic structure of the organic semiconductor iron-phthalocyanine with potassium doping has been studied by means of photoemission spectroscopy, near-edge X-ray absorption fine structure and density functional theory (DFT) calculations. The DFT study and detailed analysis of the core-level spectra permit us to suggest possible lattice sites for the potassium ions. The data disclosed filling of the lowest unoccupied molecular orbital upon doping and associated changes of the core level absorption spectra. None of the films prepared in our studies showed a finite electronic density of states at the Fermi level. (C) 2010 Elsevier B.V. All rights reserved.
|
|
| 4. |
- Grueneis, A., et al.
(författare)
-
Electron-electron correlation in graphite : A combined angle-resolved photoemission and first-principles study
- 2008
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:3, s. 037601-
-
Tidskriftsartikel (refereegranskat)abstract
- The full three-dimensional dispersion of the pi bands, Fermi velocities, and effective masses are measured with angle-resolved photoemission spectroscopy and compared to first-principles calculations. The band structure by density-functional theory underestimates the slope of the bands and the trigonal warping effect. Including electron-electron correlation on the level of the GW approximation, however, yields remarkable improvement in the vicinity of the Fermi level. This demonstrates the breakdown of the independent electron picture in semimetallic graphite and points toward a pronounced role of electron correlation for the interpretation of transport experiments and double-resonant Raman scattering for a wide range of carbon based materials.
|
|
| 5. |
- Haberer, D., et al.
(författare)
-
Anisotropic Eliashberg function and electron-phonon coupling in doped graphene
- 2013
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 88:8
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate, with high-resolution angle-resolved photoemission spectroscopy, the spectral function of potassium-doped quasi-free-standing graphene on Au. Angle-dependent x-ray photoemission and density functional theory calculations demonstrate that potassium intercalates into the graphene/Au interface, leading to an upshift of the K-derived electronic band above the Fermi level. This empty band is what makes this system perfectly suited to disentangle the contributions to electron-phonon coupling coming from the pi band and K-derived bands. From a self-energy analysis we find an anisotropic electron-phonon coupling strength lambda of 0.1 (0.2) for the K Gamma (K M) high-symmetry directions in momentum space, respectively. Interestingly, the high-energy part of the Eliashberg function which relates to graphene's optical phonons is equal in both directions but only in K M does an additional low-energy part appear.
|
|
| 6. |
- Klaproth, T., et al.
(författare)
-
Tuning the electronic structure of the trichloride honeycomb lattice by transition metal substitution
- 2022
-
Ingår i: Physical Review Materials. - 2475-9953. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Transition metal trichlorides show peculiar and versatile magnetic properties. Whereas CrCl3 is a layered antiferromagnet with potential applications as an ultrathin two-dimensional magnet, α−RuCl3 may host a spin-liquid state driven by Kitaev interactions. The interest to control their material properties by chemical modifications is immense, both from an application related and from a fundamental point of view. Here, by studying CrCl3, Cr0.5Ru0.5Cl3, and α−RuCl3 by photoemission and electron energy-loss spectroscopy, we find that transition metal substitution changes the optical properties of the host without compromising its underlying electronic structure. It does so by a Cr–Ru related charge transfer process across the Mott gap effectively opening up a new absorption channel below the principal gap edge of CrCl3. The Cr and Ru valencies as well as the respective valence band density of states remain stable for the mixed Cr0.5Ru0.5Cl3 compound. Our study underlines the potential of transition metal substitution as a means of material engineering of trichlorides.
|
|
