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.

Theory of Angle-Resolved Protoemission from Random Allots

Abstract: A theory of angle-resolved photoemission from random substitutional binary alloys is described. It is argued that this theory contains a proper account of the disorder (via the Korringa-Kohn-Rostoker coherent potential approximation KKRCPA), the surface, the LEED-like nature of the final state, and the matrix elements. The results are illustrated by comparing calculations for pure Cu and for Cu-Ni alloys.

Total Energy Calculations of Alloys: Locally Self-Consistent Green’s Function Method

Abstract: There is a growing interest in first-principles investigations of materials with broken translational symmetry, for example, impurities, interfaces, and alloys. In particular, the total energy and the electronic structure calculations of systems with an arbitrary distribution of atoms on an underlying lattice will give information essential to understanding their stability and properties. At the same time two schemes most frequently used in ab initio total energy calculations for completely random alloys, the ConnollyWilliams (CW) method1 and the methods based on the single-site approximation, as the coherent potential approximation (CPA)2, have limited applicability and reliability3. Another way of approaching the solution to the electronic structure problem for disordered systems is given by the supercell technique. In this case the three-dimensional periodicity is restored although its effect on the final result can be neglected. Then conventional band structure methods can be used. However, this approach has both fundamental and technical limitations. For instance, from the basic point of view all details connected with the smearing of the electronic spectrum and the Fermi surface in alloys are lost. From the technical point of view the computational effort increases as N 3 with increasing number of atoms N in the supercell.

On the coherent potential approximation in the functional integral approach to itinerant electron magnetism

Abstract: The so-called arbitrariness accompanying the Stratonovich-Hubbard transformation of the Hubbard model in the functional formalism is investigated in the coherent potential approximation (CPA). A dynamical theory of the CPA, which is perfectly free from the arbitrariness, and a modified static theory of the CPA, in which dynamics of the spin and charge fluctuations are taken into account partially, are proposed. In contrast with the conventional static theory of the CPA, the modified static theory of the CPA has the advantage that by means of the use of the variational principle the arbitrariness of the transformation can be removed. In the limit of a small intra-Coulomb integral, a generalised spin susceptibility is estimated and the result of the Hartree-Fock approximation is reproduced in both the dynamical and modified static theories of the CPA.

Energy Band Structure of Highly Conducting Polymers

Abstract: Ab initio SCF LCAO crystal orbital calculation (with no approximation for the exchange) in the fourth neighbor’s interactions approximation of the one-dimensional (SN)X chain resulted in a width of ∼4.0 eV for the half-filled band. A coherent potential approximation (CPA) calculation of the (SN)X and \( {{\left( {S\begin{array}{*{20}{c}} N \\ I \\ H \\ \end{array} } \right)}_{x}} \) mixed chain is in progress.