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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 paper, a method for electronic structure calculations of strongly correlated materials based on the coherent potential approximation is formulated and implemented, and the evolution of the electronic structure of the LaMnO perovskite system in dependence on oxygen deficiency is studied.
Abstract: A method for electronic structure calculations of strongly correlated materials based on the coherent potential approximation is formulated and implemented. The evolution of the electronic structure of the LaMnO perovskite system in dependence on oxygen deficiency is studied.
TL;DR: In this paper, the coherent potential approximation (CPA) equations and the static relaxations are derived with the help of group-theoretic methods, and a very fast Fourier transformation between the k space and the space spanned by symmetry-adapted coordinates is discussed.
Abstract: In a foregoing publication a self-consistent phonon theory for configurationally disordered crystals was discussed by W. Biem and the author. In this article some simplifications concerning the coherent potential approximation (CPA) equations and the static relaxations are derived with the help of group-theoretic methods. Besides the familiar reduction of the relevant matrices to block-diagonal form, a very fast Fourier transformation between thek space and the space spanned by symmetry-adapted coordinates is discussed. This allows a solution of the CPA equations without using the real lattice.
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TL;DR: In this paper, it is shown that the dynamical coherent potential approximation (CPA) theory combined with the harmonic approximation (HA) is applicable to the quantitative description of the magnetic properties in high dimensional systems, but one needs to take into account higher-order dynamical corrections in order to describe the MI transition quantitatively at low temperatures.
Abstract: Magnetic and electronic properties of the Hubbard model on the Bethe and fcc lattices in infinite dimensions have been investigated numerically on the basis of the dynamical coherent potential approximation (CPA) theory combined with the harmonic approximation (HA) in order to clarify the quantitative aspects of the theory. It is shown that the dynamical CPA+HA reproduces well the sublattice magnetization, the magnetizations, susceptibilities, and the N\'eel temperatures ($T_{\rm N}$) as well as the Curie temperatures calculated by the Quantum Monte-Carlo (QMC) method. The critical Coulomb interactions ($U_{\rm c}$) for the metal-insulator (MI) transition are also shown to agree with the QMC results above $T_{\rm N}$. Below $T_{\rm N}$, $U_{\rm c}$ deviate from the QMC values by about 30% at low temperature regime. These results indicate that the dynamical CPA+HA is applicable to the quantitative description of the magnetic properties in high dimensional systems, but one needs to take into account higher-order dynamical corrections in order to describe the MI transition quantitatively at low temperatures.
01 Jan 1994
TL;DR: The concept of re-interpreting the parameters of the Ising model in terms of effective pair-, triplet and so on interactions opens up new possibilities in computational solid state physics as discussed by the authors.
Abstract: The concept of “re- interpret at ing” (mapping) the parameters of the Ising model in terms of (onto) effective pair-, triplet- and so on interactions, opens up new possibilities in computational solid state physics. In particular in connection with the Coherent Potential Approximation (CPA), which describes perfectly statistical chemical disorder, it appears that now a combination of methods is available that allows to describe with one and the same approach ground state properties such as transport properties, as well as uniquely determined parameters for statistical mechanics. One might as well add, that within the limitations of the local density approximation also an essentially parameterfree theoretical spectroscopy (e.g. XPS, XES or AES) for disordered or partially ordered systems is at hand.
TL;DR: The off-diagonal randomness in the coherent potential approximation (CPA) is self-consistently treated by extending Nickel and Krumhansl's diagram-resummation technique CPA(2).