| 1. |
- Wessley, O, et al.
(författare)
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Final state effects in the X-ray absorption spectra of La0.7Sr0.3MnO3
- 2004
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853. ; 272-276:3, s. 1780-1781
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Tidskriftsartikel (refereegranskat)abstract
- We present a comparison of theoretical calculations of the electronic structure of La0.7Sr0.3MnO3 with measurements of the unoccupied local density of states for Mn obtained from X-ray absorption spectroscopy (XAS). We compare two different theoretical calculations of the Mn XAS spectra, one based on the local spin density approximation (LSDA) and the other one based on an atomic Hartree–Fock calculation for the Mn ions. In the atomic calculation the solid state effects are introduced through a cubic crystal field where the crystal field strength is obtained from the LSDA calculation. It is found that the atomic calculations agree better with experimental data.
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| 2. |
- Bengone, Oliver, et al.
(författare)
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Electronic structure and transport properties of CrAs/GaAs/CrAs trilayers from first principles theory
- 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
- We present a theoretical study of the transport properties of a CrAs/GaAs/CrAs trilayer. The theory was based on a first principles method for calculating the electronic structure, in combination with a Kubo-Landauer approach for calculating the transport properties in a current perpendicular to the plane geometry. We have also investigated the electronic structure and the magnetic properties of this trilayer, with special focus on electronic and magnetic properties at the CrAs/GaAs interface. Finally, we have studied the effects of chemical disorder on the transport properties, in particular the influence of As antisites at both the Cr and Ga sites.
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| 3. |
- Bengone, Oliver, et al.
(författare)
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Origin of the negative giant magnetoresistance effect in Co1-xCrx/Cu/Co (111) trilayers
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:9, s. 092406-
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Tidskriftsartikel (refereegranskat)abstract
- We present a theoretical study on Co1-xCrx/Cu/Co (111) trilayers, where a transition from positive to negative giant magnetoresistance effect has been observed experimentally, with increasing thickness of the alloyed layer. The theory, based on a recently implemented conductance calculation, reproduces quantitatively this observation, and the effect is found to be caused by alloying effects, due to a virtual bound Cr d state in the majority spin channel of the Co-Cr layer.
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| 4. |
- Le Bacq, O, et al.
(författare)
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Impact on electronic correlations on the structural stability, magnetism, and voltage of LiCoPO4 battery
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:24, s. 245107-
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of the structural stability of the lithium-orthophosphate oxide LiCoPO4 using density-functional theory within the local-density (LDA), generalized gradient and LDA+U approximation. We show that both enhanced localization and anisotropic effects provided within the LDA+U approximation are essential to reproduce the experimentally observed magnetic structure, lattice parameters, and stability of the lithiated and nonlithiated compound. Within this approximation, the intercalation voltage of 4.6 eV as well as the insulator character of the lithiated and nonlithiated compounds are recovered. Moreover, we found that the LDA+U approximation induces a strong transfer of charge from the t(2g)-like to the e(g)-like orbitals of Co as well as a significant shift of the LiPO4 band. Both effects are competing with each other and determine most of the peculiar properties of the LiCoPO4 and CoPO4 compounds.
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| 5. |
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