Vacancies and impurities in aluminum and magnesium

Chetty, Naven; Weinert, M.; Rahman, T S; Davenport, J. W.

doi:10.1103/physrevb.52.6313

Cited by 113 publications

(70 citation statements)

References 64 publications

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“…In our Al bulk systems, we obtained by means of Eqn. (2) a vacancy formation energy equal to 0.69 eV, which is comparable with experimental and numerical results commonly found in literature (for example, see Refs [4,8,9]). In slab systems, we cannot use this expression anymore as the extracted atoms belong to surface regions and their cohesive energies are different from the bulk value.…”

Section: Introductionsupporting

confidence: 76%

Quenched molecular dynamics studies on the extraction energy of aluminum atoms

Perron

Politano

Vignal

2008

Surface & Interface Analysis

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The extraction energy of an aluminum atom is calculated at 0 K as a function of coordination number and defect depth for three surface orientations [(100), (110) and (111)]. For each orientation, atoms are selected and extracted one by one. A linear relationship is obtained between the extraction energy of surface atoms and their coordination numbers (with slight variations due to the geometrical configuration of the atoms). However, the study of the influence of the defect depth on the extraction energy highlights the role played by intrinsic stress on the extraction energy.

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Section: Introductionsupporting

confidence: 76%

Quenched molecular dynamics studies on the extraction energy of aluminum atoms

Perron

Politano

Vignal

2008

Surface & Interface Analysis

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“…The necessity to use several k points instead of the ⌫ point only has also been demonstrated in the electronic-structure calculations of defects in semiconductors 24 and in metals. 25 The Brillouin-zone integration for the lowest positron band in the vacancy superlattice is easy to perform in the electron-band-structure codes such as the LMTO methods. In the case of the AT-SUP method the ͑complex͒ positron wave functions corresponding to different k points can be easily obtained by applying in the real-space grid the boundary conditions given by the Bloch theorem for the supercell.…”

Section: Methodsmentioning

confidence: 99%

“…According to the first-principles calculations the ions neighboring the vacancy relax inwards. 25,29 The magnitude of the relaxation is around 2% of the bond length. This is a rather small relaxation compared to semiconductors, for which the open lattice structure and different possibilities of covalent bond formation give a large freedom for the ionic rearrangements around vacancies.…”

Section: Fig 2 Calculated Positron Lifetimes For the Cu Vacancy As mentioning

confidence: 99%

First-principles calculation of positron annihilation characteristics at metal vacancies

1996

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Annihilation characteristics for positrons trapped at metal vacancies are calculated from first principles. The calculations are based on different implementations of the two-component density-functional theory, and different numerical methods to solve the ensuing Kohn-Sham equations have been employed. The convergence of the positron annihilation characteristics calculated within different schemes is discussed, and the positron lifetimes obtained are compared with experiment. ͓S0163-1829͑96͒07145-7͔

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“…[33] First-principles calculations of the heat of solution of Mg impurities in Al also show a positive formation enthalpy. [35] Thus, the ordering energy is negative, and because the coherency strain energy is comparable to the mixing energy dECPS w O, and thus A1-Mg is a Type II alloy. The calculated SRO of an Ahj.ssMgo.15solid solution is shown in Fig.…”

Section: Ah~=mentioning

confidence: 99%

Short-range-order types in binary alloys: a reflection of coherent phase stability

Wolverton¹,

Ozoliņš²,

Zunger³

2000

J. Phys.: Condens. Matter

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Ci3s'ri"" authored by a contractor of the Un&-StatGovernment under contraAccordingly the United States Gov. srnment retains a non -exclusive royalty-free license to publish or re. produce the published form of thie ....The short-range order (SRO) present in disordered solid solutions is classified according to three characteristicsystem-dependent energies: (1) formation enthalpiesof ordered compounds, (2) enthalpiesof mixing of disordered alloys, and (3) the energy of coherent phase separation, (the compositionweighted energy of the constituents each constrained to maintain a common lattice constant along an A/B interface). These energies are all compared agaimt a common reference, the energy of incoherent phase separation (the composition-weightedenergyof the constituentseach at their own equilibrium volumes). UnlikeIong-rangeorder (LRO), short-rangeorder is determined by energetic competition between phases at a jized composition, and hence only coherentphase-separated states are of relevance for SRO. We find five distinct SRO types, and show examples of each of these five types, including CU-AU,A1-Mg, GaP-InP, Ni-Au, and Cu-Ag. AbstractThe short-rangeorder (SRO) present indisordered solid solutions is classified according to three characteristicsystem-dependent energies: (1) formation enthaIpiesof ordered compounds, (2) enthalpiesof mixing of disordered alloys, and (3) the energy of coherent phase separation, (the compositionweighted energy of the constituents each constrained to maintain a common lattice constant along an A/13 interface). These energies are all compared against a common reference, the energy of incoherent phase separation (the composition-weightedenergyoft he constituentseach at their own equilibrium volumes). UnlikeIong-rangeorder (LRO), short-rangeorder is determined by energetic competition between phases at a j'%ed composition, and hence only coherent phase-separated states are of relevancefor SRO. We find five distinct SRO types, and show examples of each of these five types, including CU-AU,A1-Mg, GaP-InP, Ni-Au, and Cu-Ag. The SRO is calculated from 1 . first-principlesusing the mixed-space cluster expansion approach combined .

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Vacancies and impurities in aluminum and magnesium

Cited by 113 publications

References 64 publications

Quenched molecular dynamics studies on the extraction energy of aluminum atoms

Quenched molecular dynamics studies on the extraction energy of aluminum atoms

First-principles calculation of positron annihilation characteristics at metal vacancies

Short-range-order types in binary alloys: a reflection of coherent phase stability

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