Deviations from Vegard’s law in ternary III-V alloys

Murphy, Samuel T.; Chroneos, Alexander; Jiang, Chao; Schwingenschlögl, Udo; Grimes, Robin W.

doi:10.1103/physrevb.82.073201

Cited by 105 publications

(70 citation statements)

References 25 publications

(22 reference statements)

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“…However, these issues can be overcome by the special quasirandom structures approach, which makes it possible to adequately mimic the statistics of a random alloy in a small supercell. [43][44][45] The atomistic nature of the special quasirandom structure approach ensures that the distribution of distinct local environments present in real random alloys is maintained. We note that special quasirandom structures are not the lowest energy structures, but in our case about 0.02 eV per formula unit higher in energy.…”

Section: Methodsmentioning

confidence: 99%

Impact of doping on the ionic conductivity of ceria: A comprehensive model

Wang

Chroneos

Schwingenschlögl

2013

The Journal of Chemical Physics

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Doped ceria is considered as an electrolyte for solid oxide fuel cell applications. The introduction of dopants in the ceria lattice will affect its electronic structure and, in turn, its ionic conductivity. Simulation of these issues using density functional theory becomes complicated by the random distribution of the constituent atoms. Here we use the generalized gradient approximation with on-site Coulomb interaction in conjunction with the special quasirandom structures method to investigate 18.75% and 25% Y, Gd, Sm, Pr, and La doped ceria. The calculated lattice constants and O migration energies allow us to explain the behavior of the conductivity as obtained in experiments.

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Section: Methodsmentioning

confidence: 99%

Impact of doping on the ionic conductivity of ceria: A comprehensive model

Wang

Chroneos

Schwingenschlögl

2013

The Journal of Chemical Physics

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“…the energy barriers for diffusion) [16][17][18][19]. Controlling point defects such as vacancies is important for semiconductors, superconductors, and oxides [20][21][22][23][24][25][26][27][28]. A way to defect engineer the concentration and clustering of point defects in the anion sublattice (for example oxygen vacancies) is via the introduction of dopants.…”

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confidence: 99%

Defect processes in Li2ZrO3: insights from atomistic modelling

Kordatos

Christopoulos

Kelaidis

et al. 2017

J Mater Sci: Mater Electron

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density functional theory (DFT) simulations in conjunction with experimental nuclear magnetic resonance (NMR) in order to investigate the Li ion migration mechanisms. Disorder in the anion sublattice can impact the material properties and the diffusion of point defects [14,15]. This is a common future in energy related materials where intrinsic disorder and doping can influence the formation (i.e. concentration of point defects mediating diffusion) and the migration (i.e. the energy barriers for diffusion) [16][17][18][19]. Controlling point defects such as vacancies is important for semiconductors, superconductors, and oxides [20][21][22][23][24][25][26][27][28]. A way to defect engineer the concentration and clustering of point defects in the anion sublattice (for example oxygen vacancies) is via the introduction of dopants. This is effectively to maintain charge balance in the lattice [29]. For example the introduction of two trivalent dopants in the tetravalent cerium site in CeO 2 can be charge balanced by the formation of an oxygen vacancy. Therefore the introduction of trivalent dopants in CeO 2 is an efficient way to form oxygen vacancies at concentrations higher than the equilibrium concentration [29].Atomistic simulation is an efficient and powerful way to understand the energetics of point defects in energy materials [30][31][32]. The main aim of the present study is to systematically investigate the intrinsic defect processes and impact of doping in Li 2 ZrO 3 using DFT. In particular, we consider here divalent (Mg, Zn, Ca, Cd, Sr, Ba), trivalent (Al, Ga, Sc, In, Y) and tetravalent (Si, Ge, Ti, Sn, Pb, Ce) substitutionals and their association with oxygen vacancies.Abstract Lithium zirconate (Li 2 ZrO 3 ) is an important material that is considered as an anode in lithium-ion batteries and as a nuclear reactor breeder material. The intrinsic defect processes and doping can impact its material properties. In the present study we employ density functional theory calculations to calculate the defect processes and doping in Li 2 ZrO 3 . Here we show that the lithium Frenkel is the dominant intrinsic defect process and that dopants substituting in the zirconium site strongly associate with oxygen vacancies. In particular, it is calculated that divalent dopants more strongly bind with oxygen vacancies, with trivalent dopants following in binding energies and even tetravalent dopands having significant binding energies. The results are discussed in view of the application of Li 2 ZrO 3 in energy applications.

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“…It is therefore evident that the Au and Ag dissociative mechanism in Ge can described with the cBX model. This in turn implies that the cBX model should be tested in systems with complicated diffusion mechanisms and defect processes [53][54][55][56][57][58][59]. …”

Section: Discussionmentioning

confidence: 99%

Gold and silver diffusion in germanium: a thermodynamic approach

Panayiotatos

Вовк

Chroneos

2016

J Mater Sci: Mater Electron

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Diffusion properties are technologically important in the understanding of semiconductors for the efficent formation of defined nanoelectronic devices. In the present study we employ experimental data to show that bulk materials properties (elastic and expansivity data) can be used to describe gold and silver diffusion in germanium for a wide temperature range (702-1177 K). Here we show that the so-called cBX model thermodynamic model, which assumes that the defect Gibbs energy is proportional to the isothermal bulk modulus and the mean volume per atom, adequately metallic diffusion in germanium.

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Deviations from Vegard’s law in ternary III-V alloys

Cited by 105 publications

References 25 publications

Impact of doping on the ionic conductivity of ceria: A comprehensive model

Impact of doping on the ionic conductivity of ceria: A comprehensive model

Defect processes in Li2ZrO3: insights from atomistic modelling

Gold and silver diffusion in germanium: a thermodynamic approach

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