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- Smirnova, E. A., et al.
(författare)
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Effect of band filling on the pressure-induced structural transition in Mo-Re alloys
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:2
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Tidskriftsartikel (refereegranskat)abstract
- We report on a detailed investigation of the combined effect of alloying and compression on the structural stability of random bcc and hcp alloys in the Mo-Re system. We use the linear-muffin-tin-orbital Green's-function method within the coherent potential approximation (LMTO-GF-CPA) and the full-potential linear-muffin-tin-orbital (FP-LMTO) method. For pure Mo we find a bcc to hcp transition pressure to take place at 620 GPa (FP-LMTO) or 730 GPa Mbar (LMTO-GF-CPA). The calculated equation of states for Mo68Re32 alloy is in good agreement with the experimental data, and the calculated bcc-hcp transition pressure is above 400 GPa. This number is much higher than the one anticipated in earlier model calculations. The agreement between the model calculations, ab initio calculations, and the experiment is restored when self-consistent occupation numbers of sp and d electrons are used.
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| 2. |
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| 3. |
- Korzhavyi, Pavel A., 1966-, et al.
(författare)
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Defect-induced magnetic structure in (Ga1-xMnx)As
- 2002
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 88:18, s. 187202-
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Tidskriftsartikel (refereegranskat)abstract
- We show that magnetic structures involving partial disorder of local magnetic moments on the Mn atoms in (Ga1-xMnx)As lower the total energy, compared to the case of perfect ferromagnetic ordering, when As defects on the Ga sublattice are present. Such magnetic structures are found to be stable for a range of concentrations of As antisites, and this result accounts for the observed magnetic moments and critical temperatures in (Ga1-xMnx)As . We propose an explanation for the stabilization of the partially disordered magnetic structures and conclude that the magnetization and critical temperatures should increase substantially by reducing the number of As antisite defects.
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| 4. |
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| 5. |
- Smirnova, E. A., et al.
(författare)
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Electronic topological transitions and phase stability in the fcc Al-Zn alloys
- 2002
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Ingår i: European Physical Journal B. - : Springer Science and Business Media LLC. - 1434-6028 .- 1434-6036. ; 30:1, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- We report on a detailed investigation of the phase equilibria and the Fermi surface in the Al-Zn system. Our calculation are based on the density functional theory and we use the linear muffin-tin orbital method and the Green's function technique. The calculated free energies of alloy formation exhibit the existence of a miscibility gap between the alloys containing approximately 10 and 55 at.% of Zn, in agreement with the phase diagram of the Al-Zn system. Seven electronic topological transitions (ETT) were found in Al-Zn system within the stability range of the fcc solid solution. A relation between these ETT and the phase stability of the fcc Al-Zn solid solutions is established. We show that extremum points on the concentration dependencies of the thermodynamic properties of Al-Zn alloys can be explained by band-filling effects.
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