Quasichemical approximation in binary alloys

Sher, A.; Schilfgaarde, Mark van; Chen, An-Ban; Chen, William

doi:10.1103/physrevb.36.4279

Cited by 144 publications

(93 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Within a cluster expansion method [29][30][31][32]34 the macroscopic alloy is divided into an ensemble of M clusters consisting of 2n atoms (n anions and n cations) each. The total number of cations or anions is then given by N = nM.…”

Section: A Cluster Expansion For Wurtzite and Rocksalt Structuresmentioning

confidence: 99%

“…In the framework of the generalized quasi-chemical approximation (GQCA), [29][30][31][32]34 the cluster fractions are determined by a minimization of the Helmholtz free energy F(x, T ). We restrict the discussion to the mixing contribution ∆F to the free energy…”

Section: B Generalized Quasi-chemical Approximationmentioning

confidence: 99%

“…(i) The strict-regular solution (SRS) model 34 . In this case, the ideal cluster fractions x 0 j according to Eq.…”

Section: Strict-regular Solution and Microscopic Decomposition Limitmentioning

confidence: 99%

“…There is one study 27 in which the chemically disordered Mg x Zn 1−x O alloys have been simulated using special quasi-random structures 28 . In another approach 29,30 the mixing free energy of a random alloy is described combining a cluster-expansion method [31][32][33] with the generalized quasichemical approximation (GQCA) 34 . In several publications about pseudobinary alloys with the first-row elements N or O as anions 27,30,35 , this method has been applied together with an ab-initio description of total energies and atomic geometries.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOand
Schleife¹,
Eisenacher²,
Rödl³
et al. 2010
Phys. Rev. B

View full text Add to dashboard Cite

Pseudobinary heterostructural alloys of ZnO with MgO or CdO are studied by composing the system locally of clusters with varying ratio of cations. We investigate fourfold (wurtzite structure) and sixfold (rocksalt structure) coordination of the atoms. By means of density functional theory we study a total number of 256 16-atom clusters divided into 22 classes for the wurtzite structure and 16 classes for the rocksalt structure for each of the alloy systems. The fraction with which each cluster contributes to the alloy is determined for a given temperature T and composition x within (i) the generalized quasi-chemical approximation, (ii) the model of a strict-regular solution, and (iii) the model of microscopic decomposition. From the cluster fractions we derive conclusions about the miscibility and the critical compositions at which the average crystal structure changes. Thermodynamic properties such as the mixing free energy and the mixing entropy are investigated for the three different statistics. We discuss the consequences of the two different local lattice structures for characteristic atomic distances, cohesive energies, and the alloys' elasticities. The differences in the properties of Mg x Zn 1−x O and Cd x Zn 1−x O are explained and discussed.

show abstract

Section: A Cluster Expansion For Wurtzite and Rocksalt Structuresmentioning

confidence: 99%

Section: B Generalized Quasi-chemical Approximationmentioning

confidence: 99%

“…(i) The strict-regular solution (SRS) model 34 . In this case, the ideal cluster fractions x 0 j according to Eq.…”

Section: Strict-regular Solution and Microscopic Decomposition Limitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOand
Schleife¹,
Eisenacher²,
Rödl³
et al. 2010
Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…These values are considerably higher than those obtained from the VFF models. Teles et al 22 investigated strained and relaxed In x Ga 1−x N alloys using a pseudopotential plane-wave approach with a generalized quasichemical approximation (GQCA) for mixing 37 . They obtained a critical temperature of 1295 K for the zinc-blende In x Ga 1−x N, which is lower than the VFF results 15,17 .…”

Section: Previous Theoretical Calculationsmentioning

confidence: 99%

First-principles calculation of the thermodynamics ofInxGa1−xNalloys: Effect of lattice vibrations

2006

View full text Add to dashboard Cite

The thermodynamics properties of the wurtzite and zinc-blende InxGa1−xN alloys are calculated using first-principles density-functional calculations. Special quasi-random structures are used to describe the disordered alloys, for x = 1/4, 1/2, and 3/4. The effect of lattice vibrations on the phase diagram, commonly omitted from semiconductor alloy phase diagram calculations, are included through first-principles calculations of phonon spectra. Inclusion of lattice vibrations leads to a large reduction in the order-disorder critical temperature (∼ 29% and ∼ 26% for the wurtzite and zincblende structures, respectively) and changes the shape of the solubility and spinodal curve through changes in the entropies of the competing phases. Neglect of such effect produces significant errors in the phase diagrams of complex ordered semiconductor compounds. The critical temperature for phase separation is 1654 K (1771 K) for the wurtzite (zinc-blende) structures. The predicted phase diagrams are in agreement with experimental measurements on MOCVD InxGa1−xN films.

show abstract

Structure and Electrical Characteristics of Metal/MCT Interfaces

Westerhout¹,

Sewell²,

Dell³

et al. 2010

Mercury Cadmium Telluride

View full text Add to dashboard Cite

Quasichemical approximation in binary alloys

Cited by 144 publications

References 21 publications

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOand
Schleife¹,
Eisenacher²,
Rödl³
et al. 2010
Phys. Rev. B

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOand
Schleife¹,
Eisenacher²,
Rödl³
et al. 2010
Phys. Rev. B

First-principles calculation of the thermodynamics ofInxGa1−xNalloys: Effect of lattice vibrations

Structure and Electrical Characteristics of Metal/MCT Interfaces

Contact Info

Product

Resources

About

Quasichemical approximation in binary alloys

Cited by 144 publications

References 21 publications

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOandSchleife1, Eisenacher2, Rödl3 et al. 2010Phys. Rev. B

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOandSchleife1, Eisenacher2, Rödl3 et al. 2010Phys. Rev. B

First-principles calculation of the thermodynamics ofInxGa1−xNalloys: Effect of lattice vibrations

Structure and Electrical Characteristics of Metal/MCT Interfaces

Contact Info

Product

Resources

About

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOand
Schleife¹,
Eisenacher²,
Rödl³
et al. 2010
Phys. Rev. B

Ab initiodescription of heterostructural alloys: Thermodynamic and structural properties ofMgxZn1−xOand
Schleife¹,
Eisenacher²,
Rödl³
et al. 2010
Phys. Rev. B