Electronic Structure of Nanoalloys: A Guide of Useful Concepts and Tools

Tréglia, G.; Goyhenex, C.; Mottet, C.; Legrand, Christine; Ducastelle, F.

doi:10.1007/978-1-4471-4014-6_5

Cited by 2 publications

(2 citation statements)

References 43 publications

(87 reference statements)

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“…This means that the energy levels λ u i have finite values if u equals Zr or H and tend to infinity if u = . The interstitial disordered H/ interstitial sublattice of the ZrH c 2−c system, which will be the reference for the perturbation calculation, is described within the CPA [16,17], which is well suited to account for the strong diagonal disorder [41] between vacancies and hydrogen atoms. Indeed, this approximation acts on only the first term (diagonal elements) of the TB Hamiltonian (1) by replacing interstitial energy levels λ H i and λ i = ∞ by an effective average complex potential , computed self-consistently through the following iterative equation:…”

Section: Theoretical Backgroundsmentioning

confidence: 99%

Tight-binding modeling of interstitial ordering processes in metals: Application to zirconium hydrides

et al. 2020

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We present here a theoretical study of ordering processes in metal-hydrogen compounds based on a generalized perturbation method and on tight-binding coherent potential approximation. This approach is illustrated for zirconium hydrides, in which case we demonstrate that a cluster expansion of the ordering energy can be limited to effective pair interactions, the leading one being between hydrogen atoms in third-neighbor positions. These results are quantitatively confirmed by comparison to density functional theory calculations and qualitatively interpreted through orbital symmetry analysis. The method is then applied first to draw a preliminary Zr-H phase diagram and then to characterize the effect of lattice deformation on the ordering processes in zirconium hydrides.

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Section: Theoretical Backgroundsmentioning

confidence: 99%

Tight-binding modeling of interstitial ordering processes in metals: Application to zirconium hydrides

et al. 2020

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“…N-body interatomic potentials lead to a good description of surface relaxations as compared with pair potentials and are therefore well suited for surface segregation studies. Although very efficient, these potentials do not allow simultaneous adjustment of the order/disorder or demixing/disorder critical temperature of the system and the solution energies of dilute systems [18]. The analysis of the ECIs obtained by CE from ab initio calculations and by SMA potentials should lead to the determination of the interactions * fabienne.berthier@universite-paris-saclay.fr that are missing in these potentials and that are quantifiable only by advanced analyses such as the one we propose.…”

Section: Introductionmentioning

confidence: 99%

Effective site energy and cluster expansion approaches for the study of phase diagrams

2021

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We apply the cluster expansion (CE) method to determine the effective cluster interactions (ECIs) from a simple energetic model that depends on both local and global composition. This model is defined by the site energies of random solid solutions of a one-dimensional alloy Co-Pt. We explore how these local and global dependencies are reflected on the cluster interactions. The energies of the structures are not well reproduced with concentration-independent interactions. Moreover, the interactions have a larger range than the energetic model which is limited to the nearest neighbors. By fitting the ECIs on the site energies, we suggest a mean-field-type weighting of the excess variables present in clusters of large size. We show that the site energy formalism controls the size of the clusters required for CE convergence and their concentration dependence. Finally, we take advantage of the site energy formalism to describe the elastic and chemical effects that control the thermodynamics of the alloy as a function of the ECIs.

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Electronic Structure of Nanoalloys: A Guide of Useful Concepts and Tools

Cited by 2 publications

References 43 publications

Tight-binding modeling of interstitial ordering processes in metals: Application to zirconium hydrides

Tight-binding modeling of interstitial ordering processes in metals: Application to zirconium hydrides

Effective site energy and cluster expansion approaches for the study of phase diagrams

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