Phase competition in (La1 − c,Src)CoO3 solid solutions: ab initio thermodynamic study

Fuks, David; Weizman, Amir; Kotomin, E. A.

doi:10.1002/pssb.201200851

Cited by 10 publications

(3 citation statements)

References 19 publications

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“…Bulk structures have been studied with cubic supercells containing 40 atoms. For LSCO, Sr ions were assumed to occupy the lattice positions as in the structure proposed by Fuks et al [6], i.e., they were placed at the farthest possible distance in a 2 × 2 × 2 supercell. We have considered the (100) surfaces, which have been modelled with a 2 × 2 slab consisting of seven atomic layers of CoO 2 and LaO stacked alternately.…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…Thus, we decided to adopt a simple approach where we first compare the properties of the LaCoO 3 (LCO) and of (La,Sr)CoO 3 (LSCO) hosts. For the latter, we assumed a La 0.75 Sr 0.25 CoO 3 stoichiometry, which has been computed to be a stable phase by Fuks et al [6]. We considered the formation of both single and double oxygen vacancies (V O ), as well as the adsorption of CO and NO molecules at the CoO-terminated (100) surface, testing all the configurations allowed by a 2 × 2 supercell.…”

Section: Lacoo 3 Vs (Lasr)coomentioning

confidence: 99%

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On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

Glisenti

Vittadini

2019

Catalysts

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The effects of modifying the composition of LaCoO 3 on the catalytic activity are predicted by density functional calculations. Partially replacing La by Sr ions has benefical effects, causing a lowering of the formation energy of O vacancies. In contrast to that, doping at the Co site is less effective, as only 3d impurities heavier than Co are able to stabilize vacancies at high concentrations. The comparison of the energy profiles for CO oxidation of undoped and of Ni-, Cu-m and Zn-doped (La,Sr)CoO 3 (100) surface shows that Cu is most effective. However, the effects are less spectacular than in the SrTiO 3 case, due to the different energetics for the formation of oxygen vacancies in the two hosts.

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Section: Theoretical Methodsmentioning

confidence: 99%

Section: Lacoo 3 Vs (Lasr)coomentioning

confidence: 99%

On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

Glisenti

Vittadini

2019

Catalysts

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“…Further, these parameters are applied for studying disordered or partly ordered solid solutions. Such an approach was successfully used previously to explain the behavior of complex perovskites, [29][30][31][32] to analyze the initial stages of the growth of thin metallic films on a ceramic substrate, [33][34][35][36] and for the description of the phase competition in TiNiSn-TiNi 2 Sn. 21 It is based on the consideration that all of the ordering phases in the fixed crystal structure of disordered solid solutions are stable with respect to the formation of antiphase domains.…”

Section: Statistical Thermodynamics Approachmentioning

confidence: 99%

Combined electronic and thermodynamic approaches for enhancing the thermoelectric properties of Ti-doped PbTe

Komisarchik

Gelbstein

Fuks

2016

Phys. Chem. Chem. Phys.

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Lead telluride based compounds are of great interest due to their enhanced thermoelectric transport properties. Nevertheless, the donor type impurities in this class of materials are currently mainly limited and alternative types of donor impurities are still required for optimizing the thermoelectric performance. In the current research titanium as a donor impurity in PbTe is examined. Although titanium is known to form resonant levels above the conduction band in PbTe, it does not enhance the thermo-power beyond the classical predictions. Recent experiments showed that alloying with a small amount of Ti (∼0.1 at%) gives a significant increase in the figure of merit. In the current research ab initio calculations were applied in order to correlate the reported experimental results with a thermoelectric optimization model. It was found that a Ti concentration of ∼1.4 at% in the Pb sublattice is expected to maximize the thermoelectric power factor. Using a statistical thermodynamic approach and in agreement with the previously reported appearance of a secondary intermetallic phase, the actual Ti solubility limit in PbTe is found to be ∼0.3 at%. Based on the proposed model, the mechanism for the formation of the previously observed secondary phase is attributed to phase separation reactions, characterized by a positive enthalpy of formation in the system. With extrapolation of the obtained ab initio results, it is demonstrated that lower Ti-doping concentrations than previously experimentally reported ones are expected to provide power factor values close to the maximal one, making doping with Ti a promising opportunity for the generation of highly efficient n-type PbTe-based thermoelectric materials.

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Influence of Disorder in Scintillating Solid Solutions on Thermalization and Recombination of Electronic Excitations

Belsky

Gektin

Vasil’ev

2019

Physica Status Solidi (b)

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The spatial distribution of components of substitutional solid solution is nonuniform. This disorder influences optical properties, migration, localization, and recombination of secondary electrons and holes created by high‐energy excitation. The scintillation properties in such systems are studied in terms of fluctuations of the bottom of the conduction band due to the disorder of the substitutional solid solution AxB1 − xC. The simulation of the spatial distribution of the components is performed for different affinities of the components. If the creation of AA (BB) pairs is preferable (high AA affinity), the fluctuations of the bottom of the conduction band can result even in the creation of clusters enriched by AC or BC components. The scattering of hot electrons by the fluctuations of the spatial structure of solid solution at the thermalization stage is discussed. The role of clustering of solid solution in the restriction of migration and recombination of thermalized carriers is analyzed using the model of the geminate recombination of electron–hole pairs. The change of properties of some scintillators (YAG‐LuAG, CeF3‐LaF3, etc.) with concentrations of components is explained on the basis of the considered models.

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Phase competition in (La_1 − c,Sr_c)CoO₃ solid solutions: ab initio thermodynamic study

Cited by 10 publications

References 19 publications

On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

Combined electronic and thermodynamic approaches for enhancing the thermoelectric properties of Ti-doped PbTe

Influence of Disorder in Scintillating Solid Solutions on Thermalization and Recombination of Electronic Excitations

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