| 1. |
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| 2. |
- Häussermann, Ulrich, et al.
(författare)
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Alloys Bi1-xSbx under High-Pressure
- 2004
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Ingår i: Physical Review B. - 1098-0121. ; 69, s. 134203-1 - 134203-10
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Isaeva, E. I., et al.
(författare)
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Ab initio phonon calculations for Ll(2) Ni3Al and B2NiAl
- 2004
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Ingår i: Solid State Communications. - : Elsevier BV. - 0038-1098 .- 1879-2766. ; 129:12, s. 809-814
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Tidskriftsartikel (refereegranskat)abstract
- The phonon spectra and phonon density of states of the Ni3Al and NiAl intermetallic compounds are calculated from first principles using the linear response method in conjunction with ultrasoft pseudopotentials. The calculated phonon dispersion curves are in good agreement with available experimental results from inelastic neutron scattering.
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| 4. |
- Skorodumova, N. V., et al.
(författare)
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Electronic, bonding, and optical properties of CeO2 and Ce2O3 from first principles
- 2001
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 64:11
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Tidskriftsartikel (refereegranskat)abstract
- First-principles electronic structure calculations of cerium oxide in two forms, CeO2 and Ce2O3, are Presented. The 4f state of Ce is treated as a part of the inner core in Ce2O3 and as a valence-band-like state in CeO2,. The calculated ground-state and magnetic properties of the Ce (III) oxide are shown to be in agreement with available experimental data as well as the calculated ground-state and optical properties of Ce (IV) dioxide. The nature of the bonding in cerium oxide is discussed on the basis of an analysis of the charge-density and electron localization function distributions and described as a polarized ionic bond in both oxides.
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| 5. |
- Colarieti-Tosti, Massimiliano, et al.
(författare)
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First-principles theory of intermediate-valence f-electron systems
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 93:9, s. 096403-
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Tidskriftsartikel (refereegranskat)abstract
- We propose a first-principles based method for calculating the electronic structure and total energy of solids in an intermediate-valence configuration. The method takes into account correlation effects (d-f Coulomb interaction) and many-body renormalization of the effective hybridization parameter of the f system. As an example, the formation of a pressure-induced intermediate-valence state in Yb is considered and its electronic structure and equation of state are calculated and compared to experimental data. The agreement is found to be excellent for both properties, and we argue that the developed method, which applies to any element or compound, provides for the first time a quantitative theoretical treatment of intermediate-valence materials.
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| 6. |
- Mikhaylushkin, A. S., et al.
(författare)
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Fluctuating lattice constants of indium under high pressure
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92:19
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Tidskriftsartikel (refereegranskat)abstract
- Recent high-pressure investigations of elemental In have yielded controversial results. We show that the observed high-pressure face-centered orthorhombic (fco) structure can be explained as an intermediate state between two body-centered tetragonal (bct) structures with different c/a ratios (c/a < &RADIC;2 and c/a > root2, respectively). In a pressure range from about 50 to 200 GPa these two bct structures correspond to local minima of the total energy with respect to orthorhombic distortion of the ground-state bct In structure. The fco saddle point represents a tiny barrier and even at low temperatures rapid structural fluctuations should occur. Such a situation has not been identified in any other elemental metal.
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| 7. |
- Ruban, Andrei V., et al.
(författare)
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Local lattice relaxations in random metallic alloys : Effective tetrahedron model and supercell approach
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 67:21
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Tidskriftsartikel (refereegranskat)abstract
- We present a simple effective tetrahedron model for local lattice relaxation effects in random metallic alloys on simple primitive lattices. A comparison with direct ab initio calculations for supercells representing random Ni0.50Pt0.50 and Cu0.25Au0.75 alloys as well as the dilute limit of Au-rich CuAu alloys shows that the model yields a quantitatively accurate description of the relaxtion energies in these systems. Finally, we discuss the bond length distribution in random alloys.
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| 8. |
- Simak, S. I., et al.
(författare)
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Gallium and indium under high pressure
- 2000
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 85:1, s. 142-145
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Tidskriftsartikel (refereegranskat)
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| 9. |
- Andersson, David A., et al.
(författare)
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Monovacancy and divacancy formation and migration in copper : a first-principles theory
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 70:11, s. 115108-
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Tidskriftsartikel (refereegranskat)abstract
- The formation and migration of monovacancies and divacancies in copper have been studied from first-principles in order to resolve the discrepancies between previously published experimental and theoretical data. The monovacancy and divacancy formation, migration and binding enthalpies as well as the formation volumes have been calculated in the framework of a plane-wave pseudopotential implementation of the density functional theory, with full structural relaxations included. The monovacancy and divacancy formation entropies have been estimated from experimental data by performing a least-squares analysis. We show that the complete set of first-principles data, taking into account the presence of both vacancies and divacancies as well as the temperature dependence of the formation enthalpies and entropies allow one to reproduce the Arrhenius plot of the total vacancy concentration and the diffusion coefficient, both in good agreement with the most accurate experiments.
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| 10. |
- Belonoshko, Anatoly B., et al.
(författare)
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High-pressure melting of molybdenum
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92:19
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Tidskriftsartikel (refereegranskat)abstract
- The melting curve of the body-centered cubic (bcc) phase of Mo has been determined for a wide pressure range using both direct ab initio molecular dynamics simulations of melting as well as a phenomenological theory of melting. These two methods show very good agreement. The simulations are based on density functional theory within the generalized gradient approximation. Our calculated equation of state of bcc Mo is in excellent agreement with experimental data. However, our melting curve is substantially higher than the one determined in diamond anvil cell experiments up to a pressure of 100 GPa. An explanation is suggested for this discrepancy.
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