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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: In this article, the concentration dependence of the reststrahl absorption in various mixed crystals exhibiting one, two and mixed mode behavior was investigated using the coherent potential approximation (cpa).
Abstract: The concentration dependence of the reststrahl absorption in various mixed crystals exhibiting one, two and mixed mode behaviour is investigated using the coherent potential approximation (cpa). The phonon Green’s function, the impurity mode frequencies and the strength of absorption are calculated in the Einstein model from the generalizedcpa proposed by Tripathi and Behera which takes into account both mass and force constant changes. The introduction of a phenomenological concentration dependence of the force constant change parameter is shown to provide a satisfactory explanation of the concentration dependence of the experimental data for the twenty mixed crystal systems analysed. It is conjectured that the nearest neighbour force constant of an impurity atom substituted at a host site is very much different from that of a perfect crystal consisting of these impurity atoms and that both these play an important role in determining the one, two and mixed mode behaviour of the mixed crystals.
3 citations
3 citations
TL;DR: In this paper, the Mott transition in the half-filled Hubbard model with spatially alternating interactions was studied by means of the coherent potential approximation and the phase boundary between metallic and insulating phases at zero temperature was derived.
Abstract: We study the Mott transition in the half-filled Hubbard model with spatially alternating interactions by means of the coherent potential approximation. The phase boundary between metallic and insulating phases at zero temperature is derived and the nature of the Mott states is also considered. Our results are in good agreement with the ones recently obtained by the two-site dynamical mean-field theory.
3 citations
TL;DR: In this paper, the lattice dynamics of PdDx and PdHx were analyzed with reference to the coherent neutron scattering experiments of Rowe et al. and incoherent neutron scattering lineshape reported by Rahman et al (1976) Disorder in the octahedral interstitial sublattice was treated within a coherent potential approximation format suitable for treating both on-site and off-diagonal randomness.
Abstract: Lattice dynamics of PdDx and PdHx are analysed with reference to the coherent neutron scattering experiments of Rowe et al (1974) and incoherent neutron scattering lineshape reported by Rahman et al (1976) Disorder in the octahedral interstitial sublattice is treated within a coherent potential approximation format suitable for treating both 'on-site' and 'off-diagonal' randomness The authors' results lead to a substantial readjustment (upwards) in the accepted values of the D-D potential Moreover, an adjustment (downwards) is also indicated in the published value of the Pd-H potential
3 citations
TL;DR: In this paper, the authors apply the augmented space method to obtain the configuration averaged T = 0 conductivity of a parametrised, tight-binding model for s-d states in random Cu-Ni alloys.
Abstract: The authors apply the augmented space method to obtain the configuration averaged T=0 conductivity of a parametrised, tight-binding model for s-d states in random Cu-Ni alloys. The calculation is within a self-consistent cluster coherent potential approximation. The statistical clustering effects and off-diagonal disorder lead to vertex corrections and to a correction for the current term in the Kubo expression.
3 citations