Spinodal ordering beyond the lifshitz point in Cu3Pd observed by high voltage electron microscopy

Takeda, Seiji; Kulik, J.; Fontaine, D. de

doi:10.1016/0001-6160(87)90071-x

Cited by 28 publications

(5 citation statements)

References 34 publications

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“…Previous studies (e.g. [2,19,20]) that obtained L1 2 as the ground state at ≈18% referred to the ANNNI Ising model, or performed an electronic mean field approach [8]. However, negligence of S1 in the first-principles input [11] will favour interactions that are 'blind' for S1.…”

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confidence: 99%

Reinterpreting the Cu–Pd phase diagram based on new ground-state predictions

Bärthlein

Hart

Zunger

et al. 2007

J. Phys.: Condens. Matter

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Our notions of the phase stability of compounds rest to a large extent on the experimentally assessed phase diagrams. Long ago, it was assumed that in the Cu-Pd system for x Pd 25% there are at least two phases at high temperature (L1 2 and a L1 2-based superstructure), which evolve into a single L1 2-ordered phase at low temperature. By constructing a first-principles Hamiltonian, we predict a yet undiscovered Cu 7 Pd ground state at x Pd = 12.5% (referred to as S1 below) and an L1 2-like Cu 9 Pd 3 superstructure at 25% (referred to as S2). We find that in the low-temperature regime, a single L1 2 phase cannot be stable, even with the addition of anti-sites. Instead we find that an S2-phase with S1like ordering tendency will form. Previous short-range order diffraction data are quantitatively consistent with these new predictions.

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confidence: 99%

Reinterpreting the Cu–Pd phase diagram based on new ground-state predictions

Bärthlein

Hart

Zunger

et al. 2007

J. Phys.: Condens. Matter

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“…The other possible process is spinodal decomposition, 10) which is definable under electron irradiation conditions. [38][39][40] In this process, when the mean concentration of surface vacancies, which increases at a constant rate q with irradiation time t, exceeds a critical value C nu above which d 2 F=dðqtÞ 2 < 0 (F is the free energy in the binary system), the concentration wave of surface vacancies with a specific wave number k max preferentially grows and an ordered array of vacancy agglomerates with the spacings of l nn $ 2=k max is formed. According to a simple decomposition model, 41) k max can be estimated by solving…”

Section: Discussionmentioning

confidence: 99%

Fabrication of Short-Range Ordered Nanoholes on Silicon Surfaces by Electron Irradiation

Ohno

Takeda

Ichihashi

et al. 2007

jjap

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We study the dynamics of active-sterile neutrino oscillations in the early universe using full momentum-dependent quantum-kinetic equations. These equations are too complicated to allow for an analytical treatment, and numerical solution is greatly complicated due to very pronounced and narrow structures in the momentum variable introduced by resonances. Here we introduce a novel dynamical discretization of the momentum variable which overcomes this problem. As a result we can follow the evolution of neutrino ensemble accurately well into the stable growing phase. Our results confirm the existence of a "chaotic region" of mixing parameters, for which the final sign of the asymmetry, and hence the SBBN prediction of 4 He-abundance cannot be accurately determined.

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“…29. It consists of the sum of the terms proportional to the Fourier transforms of ⌽ R 1 ,R 2 ,R 3 (3) and ⌽ R 1 ,R 2 ,R 3 ,R 4 (4) . In the present paper, we assume that X k is negligible, i.e., X k Ϸ0, so that the contribution from this high-order term is comparatively small.…”

Section: ͑3͒mentioning

confidence: 99%

First-principles theory of the temperature and compositional dependence of atomic short-range order in disordered Cu-Pd alloys

et al. 2001

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We combine the first-principles, Korringa-Kohn-Rostoker coherent potential approximation based calculations of compositional fluctuations with a statistical mechanical ring approximation to study the temperature ͑T͒ and composition ͑c͒ dependence of the atomic short-range order ͑SRO͒ in disordered, face-centred cubic, Cu-Pd alloys. The fourfold splitting of SRO peaks around the equivalent X(0,1,0) points in reciprocal space is obtained in a wide T-c region. Such splitting is shown to be an ''energy'' effect caused by the absolute minima of the Fourier transform of the effective atomic interactions and related previously to the existence of nested sheets of the disordered alloy's Fermi surface. However, we find that the T dependence of the SRO peak position is mostly an ''entropy'' effect. Both the calculated T and c dependences of the SRO peaks position are in good correspondence with the experimental data. The real-space effective atomic interactions and SRO parameters indicate the tendency for longer-period structures with increasing Pd concentration, as observed.

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Spinodal ordering beyond the lifshitz point in Cu3Pd observed by high voltage electron microscopy

Cited by 28 publications

References 34 publications

Reinterpreting the Cu–Pd phase diagram based on new ground-state predictions

Reinterpreting the Cu–Pd phase diagram based on new ground-state predictions

Fabrication of Short-Range Ordered Nanoholes on Silicon Surfaces by Electron Irradiation

First-principles theory of the temperature and compositional dependence of atomic short-range order in disordered Cu-Pd alloys

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