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Coherent potential approximation
About: Coherent potential approximation is a research topic. Over the lifetime, 1930 publications have been published within this topic receiving 36805 citations.
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TL;DR: These calculations are based on the fully relativistic version of the Korringa-Kohn-Rostoker coherent-potential approximation and on the recently developed corresponding embedded-cluster method and allow a direct evaluation of short-range-order effects in substitutionally disordered materials.
Abstract: We report calculations of densities of states associated with specific local atomic configurations in substitutionally disordered transition-metal--noble-metal alloys, in particular Au-Pd alloys. These calculations are based on the fully relativistic version of the Korringa-Kohn-Rostoker coherent-potential approximation and on the recently developed corresponding embedded-cluster method, and allow a direct evaluation of short-range-order effects in substitutionally disordered materials. A discussion of our results and a comparison with results obtained for transition-metal alloys such as Pd-Ag is given.
7 citations
TL;DR: In this paper, the effects of various substitutions on the electronic structure of Co in Y(Co 1− x M x ) 2 compounds (M = Al, Si, Fe, Cu) were studied employing the coherent potential approximation as embodied in an allelectron TB-LMTO method.
7 citations
TL;DR: In this paper, the excitations of the diluted anisotropic Heisenberg antiferromagnet are studied using the coherent potential approximation by extending previous work for the isotropic case.
Abstract: The excitations of the diluted anisotropic Heisenberg antiferromagnet are studied using the coherent potential approximation by extending previous work for the isotropic case. The excitations of the system are described in terms of an effective medium, which is self-consistently determined using the CPA condition to treat the scattering of a vacancy and its shell of neighbours coherently. The results of calculations for the density of states and for the spectral weight function are presented using values of the parameters appropriate to the system (Co1-xZnx)F2. Preliminary comparison with neutron scattering data is made and a brief discussion is given of analytical difficulties in this and other similar approximation schemes.
7 citations
TL;DR: In this paper, the results of first principles electronic structure calculations, using the layer Korringa-Kohn-Rostoker method, are reported for planar faults in γ TiAl at various compositions.
Abstract: Establishing the chemical dependence of thermally activated processes which govern plasticity in intermetallic alloys requires that the dislocation dissociation reactions be determined as a function of composition. A major parameter governing such reactions is the relative fault stability as a function of composition. Here the results of first principles electronic structure calculations, using the layer Korringa-Kohn-Rostoker method, are reported for planar faults in γ TiAl at various compositions. The influence of dilute substitutional impurities on the fault energies is treated using the coherent potential approximation. The variation of fault energies as a function of binary composition (TixAl1-x where 52≤x≤49) and the addition of transition metals (Cr, Mn and Nb at 2% concentration) are presented. The influence of this chemical dependence on the stability of <101] super-dislocations is discussed, along with expected trends in the flow stress behavior.
7 citations
01 Apr 1975
TL;DR: In this article, the effect of dilution on spin waves in isotropic Heisenberg antiferromagnets is studied and the model includes only nearest neighbor interactions for a bcc lattice and spinwave interactions are neglected.
Abstract: The effect of dilution on spin waves in isotropic Heisenberg antiferromagnets is studied. The model includes only nearest‐neighbor interactions for a bcc lattice and spin‐wave interactions are neglected, i.e. the results are correct in the limit s→∞. The dynamical susceptibility X (?,ω) and inelastic neutron cross section are obtained for arrays 8192 sites randomly occupied by a concentration c of magnetic ions. For a given array the calculation is done by inverting the dynamical matrix and thus is essentially exact. Our results are as follows. For large k we find that Ising‐like resonances corresponding to different numbers of occupied neighboring sites become increasingly prominent as c is decreased. The envelope of these resonances agrees with previous results using the coherent potential approximation where fluctuations in environment are suppressed. For small k we find a single spinwave resonance broadened by the random dilution. The application of these results to MncZn1−cF2 is discussed.
7 citations