Ab initio calculations of the electronic topological transition in LiMg alloys

Abrikosov, Igor A.; Vekilov, Yu.H.; Korzhavyi, Pavel A.; Ruban, Andrei V.; Shilkrot, L. E.

doi:10.1016/0038-1098(92)90902-l

Cited by 83 publications

(46 citation statements)

References 12 publications

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“…26,27 For the calculation of random alloys we used the coherent potential approximation 28 ͑CPA͒ with an electrostatic correction to the one electron potential. [29][30][31] Within the EMTO method, the CPA was implemented in Ref. 32 and it was shown in an earlier work that the FCD-EMTO-CPA method gives a very good description of substitutional random alloys.…”

Section: Methodsmentioning

confidence: 99%

Thermodynamics of ordered and disordered phases in the binary Mo-Ru system

Kissavos

Shallcross

Kaufman³

et al. 2007

Phys. Rev. B

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We have performed ab initio calculations of the mixing enthalpy for the Mo-Ru alloy system. Both completely random alloys on the fcc, bcc, and hcp lattices as well as ordered and partially ordered structures based on the hcp lattice and a phase have been examined. Further, we have performed a ground-state search for the Ru-rich region using ab initio derived effective interactions, and find a series of structures below the tie line of the simple compounds. Using the structures from this ground-state search, we are able to make an estimation of the contribution to the total energy due to ordering effects in this system. We find unusually large deviations between calculated and experimental values of the mixing enthalpy for Ru-rich hcp alloys. Our calculations indicate, in agreement with experiment, that there are ordering trends in the system. However, even under assumption of maximal order theoretical results differ substantially from the experiment. Possible reasons for the disagreement are discussed.

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Section: Methodsmentioning

confidence: 99%

Thermodynamics of ordered and disordered phases in the binary Mo-Ru system

Kissavos

Shallcross

Kaufman³

et al. 2007

Phys. Rev. B

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“…40 Notice that in the earlier studies, 20,21 a basis set of spd orbitals and the LDA were used. Moreover, we now include multipole corrections to the ASA within the so-called ASA + M method, 34,41 and take the charge-fluctuation effects into account using the screened impurity model ͑SIM͒, [42][43][44] with parameters adjusted according to the procedure described in detail in Refs. 45 and 46.…”

Section: Computational Detailsmentioning

confidence: 99%

Core-level shifts in fcc random alloys: A first-principles approach

et al. 2005

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First-principles theoretical calculations of the core-level binding-energy shift ͑CLS͒ for eight binary facecentered-cubic ͑fcc͒ disordered alloys, CuPd, AgPd, CuNi, NiPd, CuAu, PdAu, CuPt, and NiPt, are carried out within density-functional theory ͑DFT͒ using the coherent potential approximation. The shifts of the Cu and Ni 2p 3/2 , Ag and Pd 3d 5/2 , and Pt and Au 4f 7/2 core levels are calculated according to the complete screening picture, which includes both initial-state ͑core-electron energy eigenvalue͒ and final-state ͑core-hole screening͒ effects in the same scheme. The results are compared with available experimental data, and the agreement is shown to be good. The CLSs are analyzed in terms of initial-and final-state effects. We also compare the complete screening picture with the CLS obtained by the transition-state method, and find very good agreement between these two alternative approaches for the calculations within the DFT. In addition the sensitivity of the CLS to relativistic and magnetic effects is studied.

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“…(ii) Abrikosov et al 25 and Johnson and Pinski 13 derived corrections to the CPA total energy which introduced charge correlations in random alloys. These corrections were shown to be consistent with the charge model of Magri et al Several authors subsequently used these corrections in total-energy CPA calculations to determine lattice constants and formation energies of random metallic alloys, finding significant effects due to charge correlations: Johnson and Pinski 13 estimated the total energy contribution due to charge correlations to be −1.25, −5.3, and −7.7 mRy/atom for Cu 0.5 Zn 0.5 , Cu 0.5 Au 0.5 and Ni 0.5 Al 0.5 alloys, respectively.…”

Section: Introductionmentioning

confidence: 99%

Point-charge electrostatics in disordered alloys

et al. 1996

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A simple analytic model of point-ion electrostatics has been previously proposed (R. Magri, S. -H. Wei, and A. Zunger, Phys. Rev. B 42, 11388 (1990)) in which the magnitude of the net charge qi on each atom in an ordered or random alloy depends linearly on the number N (1) i of unlike neighbors in its first coordination shell. Point charges extracted from recent large supercell (256-432 atom) local density approximation (LDA) calculations of Cu1−xZnx random alloys now enable an assessment of the physical validity and accuracy of the simple model. We find that this model accurately describes (i) the trends in qi vs. N (1) i , particularly for fcc alloys, (ii) the magnitudes of total electrostatic energies in random alloys, (iii) the relationships between constant-occupation-averaged charges qi and Coulomb shifts Vi (i.e., the average over all sites occupied by either A or B atoms) in the random alloy, and (iv) the linear relation between the site charge qi and the constant-charge-averaged Coulomb shift V i (i.e., the average over all sites with the same charge) for fcc alloys. However, for bcc alloys the fluctuations predicted by the model in the qi vs Vi relation exceed those found in the LDA supercell calculations. We find that (a) the fluctuations present in the model have a vanishing contribution to the electrostatic energy. (b) Generalizing the model to include a dependence of the charge on the atoms in the first three (two) shells in bcc (fcc) -rather than the first shell only -removes the fluctuations, in complete agreement with the LDA data. We also demonstrate an efficient way to extract charge transfer parameters of the generalized model from LDA calculations on small unit cells.

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Ab initio calculations of the electronic topological transition in LiMg alloys

Cited by 83 publications

References 12 publications

Thermodynamics of ordered and disordered phases in the binary Mo-Ru system

Thermodynamics of ordered and disordered phases in the binary Mo-Ru system

Core-level shifts in fcc random alloys: A first-principles approach

Point-charge electrostatics in disordered alloys

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