Electronic theory for segregation at the surface of transition-metal alloys

Kerker, G.; Morán‐López, J. L.; Bennemann, K. H.

doi:10.1103/physrevb.15.638

Cited by 78 publications

(10 citation statements)

References 16 publications

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“…12,13 Within the EMTO formalism we calculate the one-electron kinetic energies exactly for the optimized overlapping muffin-tin potential, so it provides an excellent ground for accurate FCD based calculations. Combined with the Coherent Potential Approximation ͑CPA͒ 14 the EMTO method is superior compared to the former approaches within the alloy theory.…”

Section: A Theorymentioning

confidence: 99%

Segregation at the PdAg(111) surface: Electronic structure calculations

et al. 2005

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An efficient procedure to calculate surface segregation profiles of substitutionally disordered binary alloys is presented. We show that a simple thermodynamic model with realistic atomic configurations at the surface region combined with the total energies obtained from exact muffin-tin orbitals calculations leads to accurate surface segregation profiles. We find that the calculated surface segregation energies in random alloys show significant dependence on the local environment of the atoms involved in the segregation process. Correspondingly, the alloy surface energy is significantly affected by the subsurface atomic layers. As an example the PdAg͑111͒ surface is considered.

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Section: A Theorymentioning

confidence: 99%

Segregation at the PdAg(111) surface: Electronic structure calculations

et al. 2005

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“…[5][6][7] For the calculation of the chemical potential of solid solutions Monte Carlo ͑MC͒ simulations 8 or analytical statistical-thermodynamic approaches 2,3,6 can be used. The MC method is characterized by a high accuracy, because it avoids additional simplifying assumptions, and can be used as a standard in statistical thermodynamics.…”

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confidence: 99%

“…[1][2][3][4] In surface segregation theory, the condition that the chemical potential is equal in all near-surface layers and in the bulk part of the alloy provides a set of equations for the atomic concentration in every layer. [5][6][7] For the calculation of the chemical potential of solid solutions Monte Carlo ͑MC͒ simulations 8 or analytical statistical-thermodynamic approaches 2,3,6 can be used. The MC method is characterized by a high accuracy, because it avoids additional simplifying assumptions, and can be used as a standard in statistical thermodynamics.…”

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confidence: 99%

Analytical correlation correction of the chemical potential of solid solutions

et al. 2005

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We derive an analytical expression for the chemical potential of disordered binary alloys using a reciprocal space approach. The main characteristic of the formalism is that it does not limit the effective radius of atomic interaction and correlations in the system. The lattice displacements caused by atomic size mismatch can be naturally introduced into this formalism. A comparison with results from Monte Carlo simulations shows very good agreement. The new analytical expression for the chemical potential can be widely applied, e.g., for the calculation of phase diagrams as well as surface segregation profiles in nanoconfined systems. DOI: 10.1103/PhysRevB.71.140201 PACS number͑s͒: 64.60.Cn, 61.66.Dk, 05.50.ϩq The chemical potential of a solid solution A − B, = A − B , where A and B are the chemical potentials of the alloy components, is a fundamental thermodynamical quantity, since, at thermodynamic equilibrium, the chemical potentials of all the parts of the alloy are equal. This condition is applied in many areas of solid state physics and materials science, including the study of phase diagrams, spinodal decomposition or surface segregation phenomena. From the condition that the chemical potentials in all product phases must be equal in systems undergoing spinodal decomposition, the concentration in each of them can be found.1-4 In surface segregation theory, the condition that the chemical potential is equal in all near-surface layers and in the bulk part of the alloy provides a set of equations for the atomic concentration in every layer. [5][6][7] For the calculation of the chemical potential of solid solutions Monte Carlo ͑MC͒ simulations 8 or analytical statistical-thermodynamic approaches 2,3,6 can be used. The MC method is characterized by a high accuracy, because it avoids additional simplifying assumptions, and can be used as a standard in statistical thermodynamics. On the other hand, simple models and analytical expressions for thermodynamic quantities are extremely important, since they not only elucidate qualitative trends but also allow us to express one physical property of the system via others. In addition, analytical approaches demand in general much less computational efforts in comparison to MC simulations.Among the analytical statistical-thermodynamic approaches for the calculation of the chemical potential, the single-site mean-field approximation ͑MFA͒ and several versions of the cluster-variation method ͑CVM͒ are commonly used. The MFA ignores correlation effects in the mutual arrangement of the different alloy components.3,9 The CVM, which takes correlations into account, 2,4,9 involves cumbersome analytic equations and a nonlinear increase in calculation time with increasing radius of atomic interaction.Real systems, such as metallic alloys, are often characterized by a large radius of atomic interaction. One source of long-ranging interactions is atomic size mismatch, which is generally present in alloy systems. It results in an infinitely ranging strain-induced interaction be...

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“…Lambin and Gaspard [27] proposed a monolayer model in which the energy change occurring when a bulk atom exchanges with a surface atom is calculated from the electronic structure of the alloy. Kerker et al [28] along with Balselro and Moran-Lopez [29] presented a multilayer electronic model in which the free energy is determined from electronic calculations and subsequently subjected to a constrained minimization in order to determine equilibrium compositions. Results for the AuCu system are presented in the paper by Balselro.…”

Section: (1)mentioning

confidence: 99%

“…Pure component surface free energy data for all the elements studied were obtained from refs. [27,28] while data used in calculating regular solution parameters and Margules constants were taken from Hultgren et al [29]. Examples of some of the values of parameters used in the computations are listed in Table 1.…”

Section: "Ab = + Vi-mentioning

confidence: 99%

Modeling alloy catalyst surfaces and bimetallic catalyst particles

Strohl

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Electronic theory for segregation at the surface of transition-metal alloys

Cited by 78 publications

References 16 publications

Segregation at the PdAg(111) surface: Electronic structure calculations

Segregation at the PdAg(111) surface: Electronic structure calculations

Analytical correlation correction of the chemical potential of solid solutions

Modeling alloy catalyst surfaces and bimetallic catalyst particles

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